SET HEADER SIP AFTER Response 4xx

Hi,

I need to set SIP header after receive response to INVITE with 4xx code.

I work in 3PCC mode and with SU 395

When i receive this code, i call gc_dropCall and HMP send automaticaly ACK paquet. I need to set "Via" header and "User-Agent" header.

I tried a lot of combinaison with gs_SetUserInfo, but nothing work.

Maybe someone found a sequence that works.

Thanks in advance

Yvan