Sam2:
????? ??? ???? ???? ??? ? ???? ??
http://hebrewbooks.org/pdfpager.aspx?req=14673&st=&pgnum=76
and
????? ??? ???? ???? ??? ? ???? ??
http://hebrewbooks.org/pdfpager.aspx?req=14675&st=&pgnum=200
Neither one really contradicts what I said. (There are two seperate issues – bittul torah and davening in the place where you learn. I only mentioned the second one.) In fact according to R’ Moshe’s pshat in the Rema, then the case is even stronger than I made it out to be for davening beyechidus, even halacha lemaiseh.
Correct me if you know of a different Teshuva that speaks about this.