importing XMI file in ARIS UML Designer.

Hello!
Can you help me
We are importing XMI file (UML 2.5 XMI 2.5.1 ) in ARIS UML Designer. 
After the import the available classes and relationships, but no models. What can be the reason?

Models were painted in power designer. Exported in UML 2 XMI 2.1. Then using Enterprice Architect transformed UML 2 XMI 2.1 into UML 2.5 XMI 2.5.1 and after this XMI file (2.5 XMI 2.5.1) imported into ARIS UML Designer without stylesheets (xsl).
Thanks!