Tshark pdml value

Hi guys. I'm trying to extract multimedia content from an MMSE dumped pcap file from command line (Bash - Linux RHEL5).

Well, with command:

tshark -R "mmse" -r mms.pcap -T pdml

i can see a smil tag nested in ip -> tcp -> wsp tags. This is the line i care for:

if a try to print it with:

tshark -R "mmse" -r mms.pcap -T pdml -e smil.smil -T fields

i get the content of showname and not of value property... i cannot get a clue about how to get value field... someone have an idea?

In second instance i want to ask you the best approach possible in writing a script or a program written in C that extract multimedia content from a MMSE filtered pcap file.

Thank you in advance, Davidone