I don't know anything about Roku equipment, but JP1-Master-1.09 lists three possible device numbers for various Roku components. The 2 XD isn't listed, but the possibilities are-
HD1100: NEC2 190.239 (Cable 2371)
HD 1000: NEC1 111 (Audio 1828 can be modified to work)
LT, XDS, 2XS: NEC1 234.194 (I don't see a corresponding setup code).
Probably the 2 XD uses NEC 234.194. If you do try to learn the codes from a remote which isn't supplied with your Roku, try to find a remote from one of the newer models.