[Gmsh] export to step and brep fails - "No OpenCASCADE model found" - ubuntu 12.04

[newsboost]

Hi all

I'm trying to export to step and brep file format, but it fails:

"No OpenCASCADE model found"

I'm on ubuntu 12.04 - I've installed quite some OpenCASCADE-packages 
(however, not developer packages, do I need that?).
I usually install things with synaptic (ubuntu package handling system), 
can I fix this problem with synaptic?

There's something called opencascade-draw and then there's oce-draw - 
currently I have the former installed as trying to install the latter 
will remove the first package. Also, I don't have lib* (openCASCADE)-stuff.

I would really appreciate if anyone in here, running ubuntu 12.04 can 
tell me how to export in the easiest way...


Thanks!