partner profile determination - output control

[Gunterdd]

Hi guys,

How is the partner profile determined from a message within a SD doc (ex: delivery) determined through Output control.

I have the following example in my system, but do not understand how it works:
For delivery 8xxxxxxxx, the LALE message type is triggered when goods issue is done on it (it's routine '1' set in SPRO for this message type).
The view of the message in the deliverry Output (Header level) is set like this:
LALE 6 (EDI) SP YYYY,
YYYY being the Sold to Party.

As for the partner profiles (transaction WE20) , i have the following entries in table EDP12:
YYYY KU SP V2 LALE DELV SHPCON
YYYY KU SH V2 LALE DELV SHPCON
QzzCLNT010 LS V2 LALE DELV SHPCON

When i trigger the ouput type LALE for my delivery, why does the system triggers an Idoc with partner profile QzzCLNT010 and not the YYYY (KU type) ?
In other terms, what are the rules from message control to determine the right partner profile?

Thanks for your help.