Lack of self in asian religions is a pride thing, not identity.
At the same time, though, I don't believe anybody has a true self. Personalities are maleable.You adapt, you learn, or you forget. I think the BPD lack of self is something different from traumatized people lack of self, or merely lack of an identity.
I think it's more like a void, with a hunger to fill it, like the other "voids" BPD has. Like trying to glue back the hair that fell from your head... BPDs "lack of self" is neurological/psychiatric, and our glances and opinions at it are probably just a small part of a wider issue. BPD or people who relate to BPD tend to be void inside and extremely detached to life... in a satisfying way, at least.
But then again, I don't know why that has to be an issue. Make plans, keep lists, keep track of what you do, and live one thing at a time... Will make no difference. Most nons have issues with that, too, they're just not so "OMG I NEED AN IDENTITY I CANT RELATE TO ANYTHING WHO AM I NOTHING I DO IS GOOD THIS IS NOT TH EBEST THING I CAN BE FOR THIS SITUATION IT WILL NEVER GET ME WHAT I WANT GGNNNNNRRRR". Keep it rational and well paced, you'll see a lot of people have issues with this, too, they just take it more graciously and rationally.
My borderline mother projected A LOT of self conscious issues stemming from her lack of identity and problems seeing herself as something "good and whole" on a lot of people. Something I picked up and dismissed as being obviously "unreal". I still think part of the syndrome is not only lacking stability of identity, but fueling with lack of acceptance of self. It's like BPDs try on different masks and one of them fit right. Well, guess what? Most things and people are crappy.
It's just cerebral whackiness, slowdown and do a countermeasure based on reality.
Reminds me of gay men and some women how have a lot of body image issues and unstable presentations and mannerisms. The need to be seen and liked is so big, it takes away realistic expectations from them.