"Import csv shape data" seems not to cover UML diagram class shape

When I download a class diagram using "CSV as shape data" and import it again a do not end with the diagram. More precisely I lost the attributes and functions parameters.
For example if I download a diagram with two basic UML classes connected together. I get the following "CSV of shape data":

IdNameShape LibraryPage IDContained ByGroupLine SourceLine DestinationSource ArrowDestination ArrowText Area 1Text Area 2Text Area 3
1PagePage 1
2ClassUML1Class1"+ attribute1:type = defaultValue
+ attribute2:type
- attribute3:type""+ operation1(params):returnType
- operation2(params)
- operation3()"
3ClassUML1Class2"+ attribute1:type = defaultValue
+ attribute2:type
- attribute3:type""+ operation1(params):returnType
- operation2(params)
- operation3()"
4Line123NoneArrow

But then if a import the previous file and export it again. I get the following "csv of shape data" file.

IdNameShape LibraryPage IDContained ByGroupLine SourceLine DestinationSource ArrowDestination ArrowText Area 1
1PagePage 1
2ProcessFlowchart Shapes1Class1
3ProcessFlowchart Shapes1Class2
4Line123NoneArrow

It would be really helpful for me to have this feature working correctly so I can generate "csv shape data" from other format particularly for .dot. I promise that I will release the converter once I get it work correctly.

Any  idea to make this import - export work?