You will find 3 picking sheet forms located under your Mas 90 Reports folder:
The picking sheet forms include a sub report. The sub report shows on picking sheet after item. The sub report does not show on the standard pick sheet form. 
MB picking sheet ACROSS form code - Does not work with allocations
MB picking sheet ROWS - should be used when allocating.
Standard users cannot select the option to print the wave pick sheet- must set company wave pick sheet option to no.
These forms can be difficult to customize so you may want to involve your Sage Partner if customization's are needed.