I don't know if this makes sense, but to get their RAID10, I first need to install it, then use the web interface to setup RAID 10. Instead I would like to have openfiler running on the RAID 10 setup as well.
I don't think that you have a significant gain by doing so. Aren't you being a little too rigid there?
It seems to me that it makes much more sense to install the OS in a separate partition, maybe on RAID1, and then create a RAID10 for your data with the help of the openfiler interface.