I have "wormery worms" in both my compost bins & unless they wriggled 90ft over concrete, tarmac and brick, they didn't come from my wormery ;)
I think they either occur naturally in the soil & he bins or may have migrated from the stable yard manure I use in the garden. I get mine from a help yourself heap & I dig down into the mature stuff which has the worms in it too. You could add some well rotted stable stuff as an accelerator if you're not seeing worms in your compost heap, although I'd expect there are loads in there if it's not dry.