For Steelhead Mobile to work with Cisco VPN Client with ASA 5500 series, you have to either configure an in-path pass-through rule in the acceleration policy (as described in the Management Console User Guide), or execute the following commands to configure Cisco PIX to allow TCP options in traffic:
PIconfig)# access-list TCP extended permit tcp any any
PIconfig)# tcp-map tmap
PIconfig-tcp-map)# tcp-options range 76 76 allow
PIconfig)# class-map cmap
PIconfig-cmap)# match access-list TCP
PIconfig)# policy-map pmap
PIconfig-pmap)# class cmap
PIconfig-pmap)# set connection advanced-options tmap
PIconfig)# service-policy pmap global
