Kenji Yamamoto did not compose the Overseas BGM for DBRB (What is included on the DBRB CES - the Japanese version of DBRB only contained the original Dragon Ball anime score by
Shunsuke Kikuchi).
Toshiyuki Kishi, a famed Japanese musician (and anime and VGM composer somewhat),
composed and arranged the Overseas BGM to Raging Blast, while
SUNAO, a Japanese guitarist who knows Kishi,
performed as a guitarist. Kishi even confirmed that he did the DBRB Overseas BGM
when I asked him that exact question. Though in this case, it's understandable, as
the overseas credits for Dragon Ball Raging Blast do not mention Kishi or SUNAO at all.
Kishi and SUNAO also did the Overseas BGM to "Dragon Ball Z Budokai Tenkaichi 3" ("Sparking! METEOR").
On a related note: Why the hell are people so inclined to quickly jump to the conclusion that Yamamoto did all of the BGM for every single Dragon Ball game?