[2.012 Rivals] Game-breaker: "ally" blocks chokepoint on strategic map

Playing the campaign map.

I had recently allied with the wraiths and needed to get an army into the swamp giants territory to do a quest for them.

The chokepoint into the swamp giants territory had 3 wraiths sitting on it,  and they Would.Not.Move.

I could not move through them.   Talking to them did no good (just brought up the usual diplomacy window).

I could not find a way to politely ask them to get out of the way,  and could not bring up the blockade quest because the #@!$(* wraiths were sitting on it.

I gave them 10 turns, then quit in frustration.

So,  two questions:

1.  does anyone know of a way to move through / switch places with an allied army?

2.  if not,  can one please be added?

Thanks!