asterisk users - Nov 2004 - snom - blinking leds on fuction keys when call is not yet established - how?

hi,

i just ported the patch of David Hinkle
http://www.mail-archive.com/asterisk-users@lists.digium.com/msg49781.html
to the current cvs version of asterisk. the theory is that the leds of
supervisioned extensions are blinking until a call is established
whereafter the leds should be constantly lit.

however it's not working.

the asterisk server is sending the following xml notify to the snom
phone (according to the sip trace of the phone) when the extension is
ringing:
    <dialog-info xmlns="urn:ietf:params:xml:ns:dialog-info"
version="11"
state="full" entity="sip:snom220@xxxx.xxx">
    <dialog id="185">
    <state>early</state>
    </dialog>
    </dialog-info>

the corresponding led is lit contantly and not blinking as it should be.

the system information of the snom phone is as follows:
Phone Type:	snom220-SIP
Version-Code:	snom220-SIP 3.52
Bootloader:	http://www.snom.com/download/snom220-boot2.1.bin
Firmware:	http://www.snom.com/download/snom220-3.52-beta-SIP.bin

he functions keys are configured:
fkey5!: dest <sip:180@snom.info;user=phone>


how can the blinking state of the leds be achieved?
is this a firmware version issue of the 3.52 i'm using?

regards
  frank sautter