PB About a visitor registrating from Jticketing.

when he has complete his Jticketing registration, and so when he is log in, he appears not with his 'NAME' but with his mail !

I mean for example instead having: HI JONES WELCOME AGAIN TO....
we have
HI RZGDGZE@RZCSFSF.COM WELCOME AGAIN TO

The probleme is that it is impossible for him (with joomla account) to change the login, so impossible to put a name instead of a mail.

what is the solution ??