We already have this enhancement open for the compatibility property:
https://glassfish.dev.java.net/issues/show_bug.cgi?id=10496
I have just added your request there also so we don't forget about it.
About choosing between v2 and v3, I am not sure I understand why it would be really difficult to deploy this in v3. If you don't want to use the --libraries option, you can also package the ejb jar as an ear and with the entity library jar placed in the ear root level lib directory?
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