It isn't getting the fired Berdan primer out, it is finding fresh Berdan primers to recap with. If anybody knows of a source, I have not seen it in print or www, and there are a lot of people wondering about keeping their funny furrin guns shooting after the Slobbovian surplus dries up.
It is possible to convert SOME Berdan cases to Boxer. If the primer pocket is smaller than .210", it is just a lot of work. There are a lot of .217" Berdans out there that I have READ can be used by hammering the anvil flat, which mostly fills the dual flashholes, milling the pocket flat, drilling a central flashhole, and crimping the rim of the pocket to hold a .210" Boxer in place.