Theses are the combos that involve doing [6]4x first right? Start charging 8 during that move. If you press C before you jump, you'll still get 5C.
I only know Seseme Street combos with Saki, pktazn. I wasn't trying to look down on you. @_@
Edit: Looking back at the wiki though, I see that there are other combos using [8]2x. In those cases, I imagine you charge during 5C since it's not jump cancelable. But I'm not entirely sure.