apm question

Try this:

when ACCESS_POLICY_AGENT_EVENT {
    if { [ACCESS::session data get session.radius.last.attr.class] ne "" } {
        set bin [ACCESS::session data get session.radius.last.attr.class]            

        log local0. "bin = $bin"

         convert this HEX string for binary format input
        if { [catch {
            set ascii ""
            for { set i 0 } { $i < [string length $bin] } { incr i 2 } {
                if { not ( [string range $bin $i [expr $i + 1]] equals "0x" ) } {
                    append ascii "0x[string range $bin $i [expr $i + 1]] "
                }
            }                         

            log local0. "ascii = $ascii"

             binary format HEX data to ascii and add to an APM session variable
            [ACCESS::session data set session.radius.last.attr.class.decoded [binary format c* $ascii]                

            log local0. "decoded = [binary format c* $ascii]"

        } err] } {
            log local0. "error = $err"
        }   
    }
}