B707-700

Okay you guys have helped in the past so I am back asking for help yet again.I want to paint a B707-700 in the livery of 1980's, the problem is I cant find one for FS9.The only thing I can think of is to paint over an existing livery. I have found one and that livery closely resembles the United livery, the problem I have is how to get rid of the old livery or create a template from that one. I am only doing this for my personal use, NOT FOR RESALE OR UPLOADING!Additionally I suck at repainting, I keep trying and it keeps me out of bars.Thanking you in advance for your considerations.Carl PS- I found the model at HJG, however they have a policy of not painting any airplane that was not flown by the airlines. They will not repaint one however they were willing to help a little.