found the answer in xdoclet newsgroup:
documentation is lacking, load-group is actually supported.
and on the getter method @jboss.load-group name="quick-info" will do the trick.
Dont know about the left-join tag support. Doesn't look like 1.2.3's xdt has it.
I think xdoclet team dont support left-join tag. If u open up the jbosscmp-jdbc_xml.xdt file from the xdoclet jar file in lib directory, you will see read-ahead tag only supports strategy page-size and eager-load-group tags under it. I think it is complicated by the fact that left-join could be recursive, means any number of levels deep, which xdt tagging mechanism may have problem with.