FSI: null element in coupled-physics

yus

hello dear all,

i am doing FSI in ANSYS7.0, and I just got a problem. It's a 2D model in the sequential physics approach.

while solving for one physics environment (say fluid), the regions of the other environment (say building) must be assigned a null element, so that it shall be ignored while running the solution for the fluid.

Here is my problem; i couldn't get the command to over-assign the building (mind here, this region is already assigned with its proper element -- plane42).

so, please, frnds, help me out....i got stucked.

i tried to use the "MESH ATTRIBUTES" from the main menu. but, even though i created (added) the NULL ELEMENT, it doesn't doesn't show up in the drop down menu of this MESH ATTRIBUTES-window. ...there is only one element type of that of the active physics environment (i.e., either fluid141 or plane42).

THANKS!!