Hi, u new to both UML designing and MyEclipse UML plugin. If it were for me, would would just start by creating my class diagrams from existing code. I doubt if this feature exist from within MyEclipse UML2? Is there a good tutorial in using UML from MyEclipse?

exlipzSnx7,
UML2 will be part of 7.5GA as an Early Access 3 release. Greatly improved, but not the final GA version. UML2 GA will ship 2 weeks after 7.5 GA as an updated available through the dashboard. At the moment we don't have any UML 2 documentation but we'll have full documentation then.

For now, you can refer to these links for help on UML:-
http://www.myeclipseide.com/documentation/quickstarts/uml_overview/
http://www.myeclipseide.com/documentation/quickstarts/uml/

p.s.:- 7.5 GA is scheduled to be released by the end of this week.