It looks like you found a couple of bugs.
1) The documentation should have indicated that the method only
returns information about tables that DataMgr has used (or been told
about). That has been fixed now.
2) DataMgr's table limitation was set up to work (incorrectly) so that
it would return the table given only if it already knew about it. I
have fixed that locally and it will be in the next build released.
Sorry for the trouble on both counts,
Steve