RRS web site comments:
"Some Bogen/Manfrotto ballheads can be modified in a similar manner, but the tapped female socket in the stem is metric 6-1.0. Buy our B2 AS II clamp and fix to the head using a M6-1.0 flat-top metric machine screw. Use LocTite type 242 (blue fluid, medium strength) to keep clamp from twisting."
RRS lists 'kits' for a number of Manfrotto heads (4x series), but does not list one for 3055...so maybe it is not possible to convert.