asterisk users - Oct 2003 - X100P and Call Waiting Caller ID on the PSTN line

Hi,

I have the following basic configuration:
- one X100P card
- two IP Phones (connected to an ATA186)

When an incomming call on X100P, both phones connected to an ATA186 rings
(configured like that in extensions.conf).
When a call is established between the two ATA phones and a call occurs from
the PSTN line, the callerid is correctly displayed on both phones (as
internal  callwaiting callerid).

I have the callwaiting functionality activated on the PSTN line.
Let's say now that a call is established between PSTN and one of the phones
connected to the ATA.
When another incomming call on the same PSTN line (Callwaiting) the number
of the new call is not displayed on the phone display (callwaiting
callerid).

It can be done something to solve this issue?

Thanks,
Dan