Hey Helmut,
I have an idea that has worked for me a few times...send someone else over to make an offer on the car. I tried to buy a 67 RS-SS for atleast 10 years from the original owners and they would never sell...maybe I insulted them the first time by offering 1000 dollars for thier car...but when I sent my brother there to make an offer, they sold him the car for 1200 dollars...I had actually raised my offer to 1500 dollars at one point. Ya just never know.
ps... I'll be glad to go over and make an offer if you cut me in as a partner!!!hahaha
good luck!!!!