Trigger Unified Messaging Service Popup after Picking Record from Pick Applet

Hello all,

Are there any constraints on Triggering the UMS Popup for showing the error message to the user after the picking of a record in the pick applet ?

If not, how to implement it ?

On the Order Header, the agent should pick the Related Order Id (the pickmap fields must be Set on the Order ) and then regarding of the conditions,

either Line Items should be transferred from the Related Order with picking and filling the fields from the pickmap,

either Message should be shown to the user informing him to Add Line Items manually from the Catalog with picking and filling the fields from the pickmap (pick mustn't be stopped),