[Users] AVPOPS manipulating header fields

Hi all I am in the need for a little assistance on how to best use some data taken from a invite request, and then create an appropriate AVP. My idea was to take the from header field, avp_write("$from", "$fromuri"); Then use it to extract the alias which belongs to this user, and create the AVP, avp_db_load("$fromuri","s:pai/$scheme0"); And then incorperate it into another AVP, in order to add a callerid, via P-Asserted-Identity, avp_printf("i:10","<sip:$avp(s:pai)@sip.domain.com>"); remove_hf("P-Asserted-Identity"); #remove org. hdr avp_pushto("$P-Asserted-Identity/request","i:10"); # set new hdr My question is, how do I best remove the port (eg. :5060) indication at the end of the from header field? Because the clients on a private IP range and my alias table does not carry the port numbers (eg. 88888888(a)sip.domain.com ). So I need to manipulate the $fromuri, by removing the port indication, before i do the avp_db_load! I was thinking of using the avp_subst function, but cant quite seem to get it to work. Can anyone help me with a smart way to solve this problem? All help greatly appreciated. Kind regards Martin Kjeldsen