John is correct. A PFD can only be a PFD, and if you sew anything onto it you have destroyed the integrity of it in the Coast Guard's view.
Are you gonna get pulled over by the PFD police and fined? Probably not, but there are reasons why world-wide, all manufacturers of even the high-end inflatable PFDs do not combine them with other use harnesses.
-- Sheet In!
Prindle 18-2 #244 "Wakizashi"
Prindle 16 #3690 "Pegasus" Sold (sigh)
AZ Multihull Fleet 42 member
(Way) Past Commodore of Prindle Fleet 14
Arizona, USA --