If you are looking at using lean in a more formal planning environment with MRP then you might want to look at how the schedule Kanban works. It will be generated based on requirements via master scheduling. This might be helpful if you are transitioning from a standard production environment as the schedule Kanban will work in a similar fashion as a production order being able to have master scheduling create a planned order and then firm that order. This is helpful when you want to have work done based on demand.

Here is a quick overview.

AX2012 R3 CU11.

Cheers

Lachlan