APM ActiveSync - Block or Allow DeviceID

What log messages are you actually seeing?

I've added some logging below:

when HTTP_REQUEST {
     Apply DeviceID restriction to all ActiveSync directory traffic 
    if {[HTTP::path] == "/Microsoft-Server-Activesync"} {
        log local0. "Activesync URI = [HTTP::uri]"
         Determine whether connection is Base64 encoded, (Windows Phone) and if necessary begin decoding process
        set string_b64encoded [HTTP::query]
        if { [catch { b64decode $string_b64encoded } string_b64decoded] == 0 and $string_b64decoded ne "" } {
            log local0.info "Successful login with deviceID"
            log local0.info "String b64decoded = $string_b64decoded"
            binary scan $string_b64decoded x4H2 IDlenHEX
            scan $IDlenHEX %x IDlenDEC
            set IDlen { expr "$IDlenDEC * 2" }
            binary scan $string_b64decoded x5H$IDlen HEXdeviceID
            set string_sentid [string toupper $HEXdeviceID]
        } else {
            set string_sentid [string toupper [URI::query [HTTP::uri]]]
        }

        if { [class match $string_sentid contains devices] } {
            log local0.info "Successful login with deviceID: $string_sentid"
        } else {
            log local0.info "Failed login with deviceID: $string_sentid"
        }
    }
}