[SR-Users] Kamailio MSRP relay problem

Hi all... I am trying to do file transfer between IMS clients (web-based WebRTC and android RCS native client). The fisrt test scenario is browser-to-browser  (WebRTC) using JSSIP stack. The second scenario is RCS-to-Broswer or Browser-to-RCS. My testbed consists of OpenIMS and OverSIP for WebRTC clients and Kamailio MSRP Relay for file transfer For file transfer I am using the msrp-crocodile library... The scenario  browser-to-browser works so far without problems. But in the second scenario I have the following problems: * When I try to transfer a file from the RCS client to WebRTC client , kamailio sends the message "error ""481", "Session-does-not-exist", however the file is sent, when I click send for the second time... * When I try to send a file from WebRTC client to RCS client, WebRTC client sends all file chunks to kamailio, kamailio receives the chunks but it doesn't forward them to the RCS client, in the console I see some errors pointed to the configuration file, however I don't know what exactly  the problem is. In the attachment please find the logs and the configuration file of the kamailio msrp relay... Can any one help me to solve this problem or give me useful hints? Thanks a lot in advance.... Medo