niranjenbabu,
Let me clarify that MyEclipse doesn’t support an integrated VeloEdit. Having said that, you should be able to add the plugin. I have done some research on VeloEdit here http://veloedit.sourceforge.net/ This mentions an update site for VeloEdit.
1. Click on Help > Software Updates > Add/Remove Software > Add Site.
2. Here specify a name and add the URL for update site as http://veloedit.sourceforge.net/updates/. Since this is a 3rd party, please verify the update site.
3. This will download the plugin for you and upon installation will ask you to restart or apply changes to MyEclipse. You need to restart MyEclipse.
4. On restart you should be all set with VeloEdit.
5. Now click on Help > About MyEclipse Enterprise Workbench > Plug-in Details, this should list you Velocity UI under plugin name.
Let me know if this helps.