Foren / Cotonti / Support / How to set pm notify to on in registration?

The problem is that, a newly registered user takes no email when i send him/her a pm, if the user had not changer the pm notify settings. 

But I want them to take emails when i send them  pms, without the necessity of editing their profile ater registration.

I really do not mention the welcome pm plugin.

Thank you in advance,

Best wishes.

Added 11 minutes later:

I have tried changing user_pmnotify field default to 1 but it did not worked. any othwer suggestions?