Yeah, I know what you mean snyperx,

I had the same problem with my suk. In the end I gave up and used the mount from an old VMAR arrow (the same as the pic below).

If you have owned a VMAR, there is a better than average chance that it broke up during a landing and that you'll have some remains

There is no doubt that the mount supplied with the sukhoi is better, however if you reinforce the firewall with ca glue and epoxy, all should be fine.