One archaic method could be the one described in C:\AVEVA\Plant\PDMS12.0.SP6\Manuals\Docs\DRAFT User Guide.pdf Chapter 9.3 Drawing Revisions.
And you can check the way the revision table is set at the bottom left corner of Aveva supplied Backing Sheets (i.e. /DRA/MAS/BACKS/MET/A0 )
Or you can define and use U.D.A.s at SHEE level. It is probably easier.
