Bogdan wrote:

not tried but you may increment the cseq by script with existing functions:
- avp_write → get the whole cseq body
- avp_subst → extract only the number part
- avp_copy → cast the string value to int value
- avp_op → increment the int value
- avp_printf → compose the new cseq body
- remove_hf → delete old cseq header
- append_hf → add new cseq hdr with new body.