​"SD/PS Assignment" indicator cannot be set

Message no. CJ119 Diagnosis If you set the "SD/PS assignment" indicator,
you must use a suitable project edit screen for the standard work breakdown structure. The screen is suitable if it contains at least two sections

. An edit screen is necessary to ensure that the numbers of the WBS elements can be uniquely generated from the sales document number (first section of the edit screen) and the sales document item (second section the edit screen).

SAP recommends that the first section have the length of 10, and the second section have the length of 6 (as is the case with number and item in the sales document). System Response

The indicator is not set. Procedure for System Administration Use a suitable project edit screen.

Hi all Dear PS/SD Experts ,

Following the Question : for assembly processing
I have created Std wbs element - cj91
std.network -cn01
in project profile - only one root is unticked .
cn08 for Allocate Material to std. network - still I am not able to set PS/SD indicator in control tab of project def
Project mask is also been used for proj def.
So in urge of need ,if possible do share your valuable suggestion
regards,
PC