Lokesh,
We do not provide intrinsic support for third party plugins, but we will try to assist you in this case. If there is a Velocity plugin which is compatible with Eclipse, you can try installing it to MyEclipse as MyEclipse is based on Eclipse.
Please make sure the plugin version is compatible with base Eclipse version of MyEclipse. Ex : If you are working with MyEclipse 2015, then the plugin must be compatible with Eclipse Luna 4.4.
If there is an update site for Velocity plugin for Eclipse, then you can install it to MyEclipse from Help > Install from Site, click on Add and add the update site. If you have access to an archived update site of the plugin, then click on ‘Archive’ in the ‘Add Repository’ window and browse to the file. Follow the wizard and restart the IDE when it prompts to.
Go to Help > About MyEclipse> Installation Details > Plugins tab to verify if the plugin is installed.
Hope this helps. Let us know if you see any issues.