What controller do you have exactly? It would have been VERY helpful if you had posted your exact model number...
I'm kind of the new Highpoint resident expert for FreeNAS(I just wrote a rather lengthy Highpoint post a few days ago.. see the link in my sig) and I'm going to spend more time than I should have because you couldn't provide us with your exact model....
I would like to point out that Highpoint hasn't supported all controllers of a given family. Controller driver support has been inconsistent even between controllers of the same family. I had to submit ticket 1704 to get the driver fixed. I submitted FreeNAS ticket 1704 to add support to the 4320, 4321, 4311, and 4310(the 4320 was the only card supported by the driver!) as well as add the 3560 and 3530(the rest of the 35xx series IS supported and if you went by the website you'd buy the $900 3560 to find out it doesn't work but the website says it should!) One of their controllers on Newegg is listed as having FreeBSD support but the feedback says FreeBSD is NOT supported at all. Another feedback comment on Newegg for a 27xx card says you have support for 8x but not for 9.x and Highpoint has said they do not intend to support 9.x+.
Anyway, here's what I found from a search of the Highpoint drivers for the 27xx series cards: (link I used is
http://www.highpoint-tech.com/USA_new/product_support_sas6.htm)
2722/2720SGL-There is no driver to download from the website. Either it's built-into FreeBSD or there actually is no driver for FreeBSD. Considering the manual does not mention how to setup the driver in FreeBSD I'm going to assume it is not supported. (See below 271x and 272x...they're website is confusing)
2782/2760/2760A/2744/2740-Again no driver is available at
http://www.highpoint-tech.com/USA_new/product_support_sas6.htm#. There is a WebGUI so my first reaction would be that FreeBSD is supported. But per a comment on Newegg(
http://www.newegg.com/Product/Product.aspx?Item=N82E16816115095) the support for FreeBSD is limited to 8.x. At
http://www.highpoint-tech.com/USA_new/CS-series_rr276x-rr274x.htm (WHY are the drivers not at the first link I mentioned in this section, but at this link?) is a series of drivers.
2782 - Driver at
http://www.highpoint-tech.com/BIOS_Driver/RR2782/FreeBSD/rr278x-bsd-8.2-v1.0.tgz appears to be written for FreeBSD 8.2. It's NOT a source code, so support is limited to what versions of FreeBSD will work with the .ko file. Of course, there is a chance that support is built into FreeBSD 9. But based on my experience with driver support from Highpoint I think it's much more likely support is limited to FreeBSD 8.2. The driver may work on 8.0 and 8.3, but I wouldn't expect it to. I wouldn't recommend this controller because it's very likely when you go to FreeBSD 9.0 you'll lose support for this controller. You would have to test this yourself if you have this controller. If it doesn't work you are pretty much SOL.
2760/2760A-The driver at
http://www.highpoint-tech.com/BIOS_.../v1.0.10.0908/rr276x-bsd-8.0-v1.0.10.0908.tgz is another .ko file. While it is compiled for 8.0, it may work on 8.2 and 8.3 As above, there's a chance it's built into FreeBSD 9.x+ but I wouldn't count on it. You would have to test this yourself if you have this controller. If it doesn't work you are pretty much SOL.
2744 - The driver at
http://www.highpoint-tech.com/BIOS_Driver/RR274x_3x/freebsd/rr274x_3x-bsd-8.0-v1.0.10.0712.tgz is another .ko file. Like above, it is compiled for 8.2, but it may work on 8.2 and 8.3 Also as above, there's a chance it's built into FreeeBSD 9.x+ but I wouldn't count on it. Again, if you have this controller you'll have to test it yourself. If it doesn't work you are pretty much SOL.
2740 - The driver is at
http://www.highpoint-tech.com/BIOS_Driver/RR274x_3x/freebsd/rr274x_3x-bsd-8.0-v1.0.10.0712.tgz is again a .ko file. File is for 8.0, but may work on 8.2 and 8.3 If you have this card and you want FreeBSD 9.x+ support you'll be on your own to test and get it to work.
Did you notice that the link for the 2740 and 2744 aren't the same, but a SHA256 check shows the files are identical. Someone is VERY poorly organized(which I already knew).
271x and 27x driver is at
http://www.highpoint-tech.com/BIOS_....0.10.0719/rr272x_1x-bsd-8.0-v1.0.10.0719.tgz. It is a pre-combiled binary(.ko) so support for future FreeBSD versions is not expected. The file will work on 8.0, and may work on 8.2 and 8.3, but 9.x+ is very unlikely. You are on your own to test/verify this controller on future versions.
Basically, .ko files are useless for the community to support. If Highpoint releases the driver then great. If they don't, too bad for you. I was able to get my controller (RocketRAID 3560) to work because the source code for the driver is what Highpoint provided for the 35xx series and 43xx series. Since the source code for the whole 27xx family is not available(at least I couldn't find it anywhere) you are at the mercy of Highpoint to release the driver for current and future versions of FreeBSD.
My advice is this: If you can get the controller to work on FreeNAS right now you are lucky at best. I wouldn't bet any kind of money that when FreeNAS is based on FreeBSD 9.x+ you will ever get the card to work. I would find an alternative controller to use in your server. As FreeNAS begins using FreeBSD 9.x you'll be on your own to fix security vulnerabilities and other bugs because you are using a controller that cannot be supported by the community and isn't supported by Highpoint at the current time. Being that FreeBSD 9.0 has been out since Jan 2012 I'd say Highpoint doesn't intend to support any of the 27xx controllers on 9.x. The 27xx controllers are at from 2010, so I'm not surprised they've discontinued support for their old line of products.
So.. in conclusion.. good luck!