[SR-Users] 'subst' request for message body (SDP)

Hello, can anybody give me a hint, how I could delete the _empty_ (blank) last line of the message body / SDP (it consists of #012#015 only)? This blank line is the rest of the original MIME message, which was reduced to a standard message with content SDP only by kamailio-3.3.4, which is principally working fine. I´ve tried using the textops functions "subst" and "subst_body", but they do not behave as like as real SED. When I try this string manipulation with SED, it is working fine with [sed '${/^$/d}']. But the subst implementation does not support the additional parameters '${' / '}'. Does anybody know how to delete the last line of the whole message? regards, Klaus P.S. the end of the message looks like this: [...]#015#012a=rtpmap:8 PCMA/8000#015#012a=ptime:20#015#012#015#012