Convert HTTP iRule to TCP

I tried creating an iRule using the TCP::collect and TCP::payload command. I am trying to use the scan command to parse the data I need. This is the scan command I am using, but it is not working, "set scan_ct [scan [TCP::payload] {%[^\]\%s} 1 sessionid ]". here is a capture of the payload I am trying to scan and the highlighted data is what I need to parse. What would I change the scan variables, {%[^\]\%s}, to in order to get my data?

POST /Epic HTTP/1.1 User-Agent: ThinClient Host: server Content-Length: 98 Content-Version: 1.0 Content-Session: 6000ec8-6f72-7yac-a334-cf657bcc2e52 Content-Type: application/smart-message ^������NX������¤þá�»T|ó<­Ó܉6Âjè��������:����������������������������������)��������������False��������������������������������������������en-US��