According to
JV44 and
CDwiki, Tsukasa has an alias, .SDSG, which he use to use back then. The only album that lists him using this is RE-ESSENCE for 3 of the songs neutron re-mixed, proton, and Crystal Highway re-mixed. Possibly this alias was used as well in his earlier releases, but because of the rarity we'll never know for a long time, or even not at all. His first album is up for sale as DL so maybe I'll place an order there and see if that gives any insight for the name credited.
I also put a variation of his name as well, one in all capitol letters (judging by the Starry Sequence page
@ CDwiki and the primary one that hes been using for now.