Get a specific value from an ASTM segment in Routing Rule

Hello.

I have a business process with an "ASTM" class : 

Inside this process i have a business rule. Inside this rule i want to get a specific field inside the message :

So i will use the same logic for HL7 messages. Here is the "path" to the segment and the field : 

So i will use this inside the routing rule like i did for HL7 messages. 

i have tried MUCH prefix like "ASTM" "X12" "ESI.X12" ..... I only got errors like << PROPERTY DOES NOT EXIST >> 

Can someone tell me what i'm doing wrong ?

Thanks.

Thomas.