Put the SIG code and the URL like you normally would, then click submit, it will say it's too tall like you said, then delete the URL and the SIG code and re-enter it again, then click submit, and it should work.

It still didn't work

That's strange...I have the Sonya one and all I did was cut and paste the URL it gives you into the signature space.

I just tried to do one and it seems the system has changed (judging from the fix offered). There is no submit button. There is no deleting. You copy/paste it, a button pops up saying 'to tall, resetting', and the html is gone.

Looks like we are out of luck, la sigh