Create a Step-CAD-Assembly-Model with three steps:
1. First you must convert the Step-File with a Freeware-Tool into a STL-ASCII-File. 2. Than import the STL-ASCII-File in a 3DVBVIEW-MUP-File with 1 part. 3. Now you can converted the MUP-file to a MUP-Assembly-File with 11 Parts.
Step 1, 2 and 3 can very easily be combined into one step by yourself and the black MS-DOS window can be hidden. But the step STEP to STL-ASCII is necessary.