asterisk users - May 2005 - How to config call out pstn by sip in a meetme bridge application?

Hi, all

I have application with asterisk.  1 sip user and 2 or more pstn user start
a conference with meetme.

SIP
user(PC)=======>SER=========>*<=================GW<------------PSTN
1
				      MEETME		     ^
	
|-------------------PSTN 2

SIP user start the conference by dial a extens 9000 which is connected to a
meetme room 9000. 
When this sip user start this call, can asterisk auto call the pstn users to
attand this meeting? The pstn user can by call by SIP.
For test, we can use handcode pstn number. 
Can someone help me for this?

Jiangzhou
Best Regards