The arch looks like this

SBC1 <-------- SIP-Router (Kamailio) <------------- Asterisk

Asterisk sends an invite to kamailio using "sip:" as request uri scheme, but SBC1 expects that invite to arrive using tel:, is there a way to change this in kamailio and  forward that invite? Something like:

$ru = "tel: +" + $rU;

Thanks!!!