How to set thinkfinger auth with failures ignored?

Hi there

I have set up thinkfinger PAM authentication using Jon Oberheide's package (see https://launchpad.net/~jon-oberheide/+archive). It is all working quite well, except that I am getting quite a lot of false negatives when I attempt to log in with fingerprint using GDM. This requires that each time that happens, I must re-enter my username.

Is there any way that I can configure PAM so that each time thinkfinger reports a wrong finger scan (i.e. scan OK, fingers don't match) it instead allows me to scan again, without registering a failure?

Cheers
JP