kazza-i also am not able to tap into alternate selves. i do EMDR therapy, and it is SO HARD. she constantly asks "what does that part of self feel?" and i constantly think, "there are no parts! i'm just me!" i also can NOT "feel" things in my body. i know when i am really nervous, but subtle things, no clue. sooooo i have no advice, but i do know how you feel. it is so difficult.
for example i was describing a scene from childhood where my dad suddenly took my cat out of the house (he hated cats), and siad he was taking him back to the pound. of course i was upset, and ran after the car, crying. she asked what i felt in my body as i was saying that story...and (like always) i just sit uncomfortably for awhile and go "ummm. i don't know. i feel the same." that is awkward enough, but then she had me imagine an alternate scenario that would have ended differently. i couldn't imagine any different ending, because that is what happened! it was an epic failure, to say the least