modify CAM_CONFIG_OPTS

[liuyiling_elaine@gmail_com]

I am using CESM1.0.5 to do 20Centrury all forcing historical runs.  My component set was B_1850-2000_CN. The default value of "CAM_CONFIG_OPTS" in "env_conf.xml" was "-phys cam4".   I tried to modify the value of "CAM_CONFIG_OPTS" to "-phys cam3_5_1" . The running was successful, but a weirded thing was although I had changed it in "env_conf.xml", I found in "cam.buildnml.csh", it was still  "cam_physpkg   = 'cam4' ", and the results made no difference either. Then I checked the configure file and found an annotation saying "# For backwards compatibility accept cam3_5_1 as an alias for cam4."
My questions are:     Is "-phys cam3_5_1" available in CESM1.0.5 ?     Is there any way to force the model to use "-phys cam3_5_1" ?