Uploaded to the E-Courier is a Seal Weld drawing with a little more detail.  It shows the construction detail for the seal weld.  Please incorporate this into the body flange design.  As you will note, the weld is applied behind the bolts, instead of in front, thereby eliminating the air path through the bolt holes.

Note Added 15 May 2007 - There is no body gasket required at the seal weld.  The 'TYP 3 PLCS' comment was an error on my part.  The only locations required for seal weld are the body flanges, not the body to head flange or the body to bottom cup flange.