Hi,
It is always tricky getting the breakpoints to hit in the login code. What user did you use for the breakpoints? Make sure they are remote breakpoints 
. Since if it is a login class, you can't be authenticated yet so I am not sure of the user you will be running as, if that makes sense? (I think it may be user "SAP" ?)
What you could do is add an implicit enhancement of an infinite loop at the top of the class and intercept this in SM50. Slightly hacky and not recommended on a system that is in use by others!
I am not sure of another way round this. Perhaps setting up a specific login user by way of an external alias? Or creating an ICF node that has the handler defined as the login page?
You also didn't say what your issue with the login page was?
Oli