Compile DSNIFF package on a FritzBox from AVM/VoIPSniffer

I really have just 50,- USD for this project as budget!: I have a FritzBox 7050 from AVM ([login to view URL]) which runs some kind of linux. I want to compile the DSNIFF package with all parts like webspy, etc... I also am looking for a VoIP based sniffer which just records all VoIP SIP traffic into WAV files on the harddrive and is so easy to handle like the dsniff package. Budget 50,- USD