thanks dave for responding.

i was able to solve my problem in a efficient way by not caring about vertex number order at all. instead i did all i wanted to do for laying out uvs on a copy of my mesh and afterwards transfered the uvs with attribute transfer back on the orginal, this way keeping the vertex number still intact and transfering the uv job.
i have not checked uv master by now but i sure will try it in the near future.
thanx for support again.