Prevent move to from aborting?

Hey all,
just started on pathfinding for my RTS game and need some help on a certain thing:
I currently remove the navmesh under my buildings so that the units run around the buildings and no into them (getting kinda stuck on the wall otherwise).
However when moving units to construct a building i spawn a waypoint in the middle of it (i want to keep that part if possible).

The problem: Navigation ALWAYS gets aborted because the waypoint is not on the navmesh and thus not reachable.
Wanted: The unit should still run to the building until it overlaps with the vicinity of the building.

Question: Is there any way to just tell the move-to / AI move to function to stop it from aborting?

Thanks for your input!


Are you rebuilding the mesh at runtime?

ok what i have done so far:
I set the navmesh to rebuild at runtime and added a navmodifier to my actor. I set the navmodifier type to obstacle instead of null. Now my units path to the building almost correctly and path around the building when it is not targeted. My only problem are the units themselves now. I tried to add a navmodifier to the units and set them to obstacle too. But now the units get stuck in their own navmodifier and basicly move and turn on the spot. (Looks like a weird breakdance.) I will post updates here once ive found a solution.