Outbound dial using SLAStation()?

Hi, Now i have my PBX with SPA942 Phones, and i configured each one using SLA.
Now i’m using asterisk-1.4.x.

Ok all run good, exept one thing, when i press the LED1, i’m able to dial directly via Zap/1 without dial plan, (100% directly)but, how can i configure a dial plan to it?
I mean, i don’t want call start with 1,etc… i don’t know how to do it.

I have this in sla.conf

[line1]
type=trunk
device=Zap/1
ringtimeout=14
barge=yes
hold=open

and this in the phone context
[phone1]
exten=>8203_line1,hint,SLA:8203_line1
exten=>8203_line1,1,SLAStation(8203_line1)