Thank you all! I'm sorry that my question was a bit unclear. I didn't know that FKEY will also connect two vertices -- I only thought that it created faces. This will solve my problem!

Hexagon 2 has a nice feature: if you press SHIFT (or is it CTRL?) when editing/moving a vertice, the vertice that you are moving automatically snaps to the closest other vertice.

www.oscillator.se/3d - Shade tutorials and Poser freebies.