Special stock indicator not getting determined in outbound delivery to vendor from VL01NO

Dear Experts,

Below is my business scenario.

I get vendor owned RTP material from vendor into my EWM managed plant and storage location. This, I return it to vendor on a regular basis. To create return delivery I use transaction code VL01NO.

I have maintained basic configurations of delivery type, delivery Item category and determination. When I create the Return delivery special stock indicator is not getting determined at delivery Item.

Please suggest if I am missing any configuration.

Looking for the support.

Regards,

Pranab