Scalar in fluent 4.5

Newbie

Hi all there Hope somebody can help me. I'm solving a scalar function in fluent 4.5. I'm patching the boundary cells for the scalar equation and activating the convection features for the scalar. When I use the "allow patching boundary cells" feature,(solve->control->numerics->allow patching), then the scalar function decreases sharply to zero, (about 10 cells from the boundary) but the boundary cells retains the constant value I gave them (this last is correct). Fluent behaves the same even if I increase the velocity inlet value to a quite high value. When I deactivate the patching boundary feature the scalar is correctly advected but the boundary cells does not retain the value I need.

Well hope somebody is still working in fluent 4.

Thanks in advance

Arturo