With the new i6000 phones there is no dial selector function to select DND so I programmed a button as DND. My customer is saying that calls are not being sent to VM when DND is on.
I know I can use FWD 605 but it wants to confirm the destination each time. What is the interaction with VM when blocking or call forward are enabled in VM?
Samsung docs to clear on this.

There was something funny with DND forwarding years ago, but that was fixed.

If you have a DND forward destination, enabling dnd should make it forward to that destination, disabling dnd should then go back to whatever call forwarding was set before dnd was activated.

I havn't played much with the 6000 series other than to get the EHS working.

With the i6011 when you select DND from the Function menu there is no option to confirm. What I did not realize is that there are two DND options, one with forwarding and the other without.
You would think that setting DND from MMC 722 it would follow what was set in MMC 316 but with my testing it does not.
Also I do not understand why camp-on has to be set so that a call to a busy station gets forwarded, why would the system not see the busy status of a station and respond accordingly?

Unless camp-on is on by default I've never had that issue.

Just set busy forward (or preset forward with preset busy turned on) and then as soon as you dial the busy station it follows the busy destination.

I have seen the system do strange things with ISDN lines and call wait to set off in the DID table though (such as route the 2nd caller to the operator group)

In mmc102, did you put vm port(eg.519) in "T/S No" column under DND Forward?