PHPAGI: Is it possible to add SIP-header?

I want to add a SIP header to a call, directly in extensions.conf it seems to work, but not as flexible as it would be with php.

Does anyone know if it can be done ?

So what I’m looking for is something like this:
$agi->SIPAddHeader(“P-Asserted-Identity: NewText sip:111@”);

I don’t think there is a function $agi->SIPAddHeader , but maybe there is another option to do something like this…

Thanks for any help,

I would use Kamailio for that…

but, why do you need that?