that's what I feared... SGI offers me a upgrade for 700$. I think that's fair.
I am going to try out the script "Connect Poly Shape v3.0" which I just found at http://www.highend3d.com/maya/mel/?section=modeling
which should simulate subd's conversion. I hope it's what I am looking for.
THX for your help
PS: Maya 4.0 Users: Do you know of any other scripts or plugins?
When the only tool you use is a hammer, every problem begins to look like a nail.