I just looked at the package, and I'm not so sure. I see the commit and rollback functions, but I can't seem to find a begin transaction function. Perhaps the query method would let you put the insert and select in the same statement. I use the DBI package, rather than DBIx, so I'm just guessing.
--roboticus
Comment on Re^3: Finding value of primary key (autoincrement) from last-inserted row with DBIx::Abstract and postgresql