Hi
As per my knowledge in Axapta both of your requirments cannot be handled in core Ax, however a work around can me created to these requirements
My suggestions
1. For inventory reservations, create a new warehouse say reserved stock and move the stock to that warehouse using movment journal, enforce constraints that sales order cannot be made on the reserved stock warehouse.
2. To suggest you on this, i would like to know whether u are using production module?
i am avlbl in gtalk and sent an invitation also
Rgds
KrishnaPrakash