you need to support hold, that should work but i have a bug sometime it doesn't work...
but your unit in munich can still do his support because the other unit that supports hold can hold of the enmy move...

In the case of a support hold, any attack (except by you) will cut that support.
In the case of a support move, if you are dislodged or if a territory other than the one you are supporting a move to attacks you, then the support will be cut. And you can't dislodge yourself.

Clear as mud?

steephie22, a support hold on Munich will not keep Munich's support move from being cut.

Any move by an enemy against a supporting territory cuts that support, regardless of other orders. Support holds don't help. Standoffs don't help. If he moves against your supporting territory, you're out of luck.

The only exception is in a specific convoy situation. From the rule book:

13. Support is cut if the unit giving support is
attacked from any province except the one
where support is being given.

14. Support is cut if the supporting unit
is dislodged.

15. A unit being dislodged by one province can
still cut support in another.

21. A convoyed Army doesn’t cut the support of
a unit supporting an attack against one of
the Fleets necessary for the Army to convoy.
(This supersedes Rule 13.)

@AndyBer - You are correct. My comment was too broad. I said "Any move" when I should have said "Any move except one from the territory being attacked."

As far as "rule 21" above goes, I'd say it's the natural conclusion of rule 13. A convoyed army and the fleet convoying it are, in several cases, considered one in the same unit where these sort of things are concerned.

Even "Any move except one from the territory being attacked" is too broad. If the territory being attacked attacks the support AND DISLODGES IT, then that support IS cut.

For example, England has Army Ruhr, Army Holland. Germany has Army Kiel, Army Munich, and Army Berlin. Holland attacks Kiel (supported by Ruhr). Kiel attacks Ruhr supported by Munich and Berlin moves to cover Kiel.

In this situation, Kiel's move against Ruhr succeeds, dislodging Army Ruhr. Its support is CUT. This means the Holland move is unsupported, and it will be bounced by Berlin.

BUT. Add French Army Burgundy, which supports the hold of Ruhr. Now Ruhr is not dislodged. In this case, Kiel is attacking Ruhr, and Ruhr is supporting an attack into Kiel, so its support is not cut. Holland's move succeeds, Kiel is dislodged.

So here we see that if you're attacking a territory that's supporting an attack against you, you CAN cut support, but you have to dislodge it in order to do so.