.Map :: MoHAA Mapping

Hi!
I hope you can help me a little bit with your big knowledge concerning working on MoHAA maps! Within the last months I've created many good looking maps for MoHAA and I almost reached the completion of every map. But a few problems were set up while working with MoH:Radiant. Before the maps were getting more and more bigger, the fps was above 150 and now if the map is getting bigger and more brushes are included, the fps-value is going to decrease continuously; sometimes lower than
20 fps. Once I've read in a map-editing-tutorial about using VIS
for increasing the frames. The leafgroup effects, that in the one
brush you can't see the content of the other one. So that means
that possibly placed trees or bushes don't have any effect on the
frames-value. Therefore I tried it on a small test-map and it
definitely worked! So I also tried this on my big maps, hoping that
works great, but it never worked on my maps. (No one of those are
bigger than Southern France, so they aren't very big) I really
believe VIS is the solution for my frames-problem, but I'm not able
to get this working. I would be enormously glad, if someone could help
me!
Thank you very much in advance,
Captain Den

its like reading the same post's over and over, This was just talked about.
Might want to do a search for vis problems