Naca owner occupancy lien

NACA $25K silent lien - can it be 'bought out'?

We have a NACA mortgage that's a great interest rate, and we're wondering what our options are as far as removing the silent second. We're considering taking out some equity and wondering what our options are. I seem to recall that you can request permission to take out a second, but considering the exercise in patience that is NACA, I don't know that I have the strength to go through that hurdle. I know we could refinance the entire loan and abandon our NACA relationship, but we have no intentions to sell the home before the 30 year mortgage is up, so we'd actually come out ahead financially (by a long shot) buying out the $25K lien rather than refinancing the entire mortgage. Is this permissible? Can you pay off the $25K lien, ending your relationship w/NACA, while keeping the mortgage you obtained through NACA?

Also, I can't seem to find the lien paperwork in my mortgage file. It's been a few years, so it's possible I filed it elsewhere, but this file has all the other closing documentation, so I can't imagine why I would have put the lien documents elsewhere. What is the document called or what might it look like? Would I be able to obtain a copy through the county recorder? I'm in California, if that makes a difference.