Sign up for SOTA and put in a spot while you're out there or ask someone who you contact to spot you (if they participate). Also, it's valid to get a contact through the repeater to QSY to 146.52 and get your official contact that way.
The Signal Stick is a quarter wave whip and would benefit somewhat from a counterpoise wire. That said, I use a Signal Stick on my VX-7 for SOTA too. I set the radio and antenna up as an integrated unit into my pack, then pull a speakermic around to my chest strap. I tend to call CQ right as I hit the summit to kind of prime things, so it certainly works.
Chris