I've tried a couple of different combinations that should add Dexterity to Damage with Unarmed/Handwraps attacks, and they don't work.

I have a monk/ranger with Weapon Finesse and Improved Weapon Finesse from the Deepwood Stalker. This put the tag "Dexterity to Damage" on my equipped handwraps (on various ones actually), but in tests the damage results were obviously using my strength.

Out of curiosity, I made another toon that was Rogue/Monk with the Dagger in the Back enhancement and Weapon Finesse, with the same results (handwraps showed "Dexterity to Damage", but no increased damage). I even made it more drastic by having a 6 strength and 20 dexterity, with damage results between 1 and 9, not including crits (unarmed strike damage with +2 handwraps was 1.5(1d6)+0, and should have been 1.5(1d6)+7 if Dex was used).