The option in the BAS component is grayed out if you still have a software configuration containing a device software bundle. If the software configuration is assigned to users/groups, you won't be able to delete it until you remove the user/group assignment.
In the IT policy, go to the Desktop Only tab and set the Force Load Count IT policy rule to 0. Have the user connect to Desktop Manager again and see if this forces the update on the device. This rule doesn't apply to Web Desktop Manager 5.0.x.
Just to verify, you did create a device software configuration that contains the device software bundles and then associated this to a software configuration right?