I have a Panzer clone. It has a floating 510 pin. If you screw your atty all the way onto the
mod it will push that pin in.
If your atty is flush with the top of the
mod, remove it, take off the top part of the
mod and push the pin up towards the atty. Reassemble it all without screwing the atty all the way onto the mod. Put he battery in so it's setup snug inside then tighten the atty a bit more, gently.
Let us know if that helps.
ETA: BTW, I would not use an UltraFire battery in any mod. Too risky. A VTC4 bought from a reputable supplier is much, much safer.