Schema composer doesn't work with UPCC3 models

[Geert Bellekens]

There are several issues when trying to use the Schema Composer on a UPCC3 model

- An «MA» element doesn't show up in the left when when dragged into the schema composer. This appears to be something specific about the stereotype, because adding a second stereotype somehow overcomes this problem.
- «ASMA» and «ASBIE» relations don't show up on the «MA» and «ABIE» elements. The associations part remains empty.

Reported

Geert