Why The Model Variants Block in Simulink forces I/O signal dimensions to 1x1?

I try to include some referenced models as variants of a Model Variants block (MVB) in Simulink. The input signal of the block is frame based.

However, A conflict arises at the input as well as at the output of the MVB. The signal I pass to the MVB is a fixed size NxM matrix, and such should be the output. Even if the referenced model is a simple line connecting in and out ports, the parent block diagram expects those signals to have dimensions 1x1.

In the documnetation of that blokc there is nothing about frame based signals. Please help Luca

[Luca Barbiero]

I solved by setting the proper signal dimensions in the input port properties at the referenced model level.

But isn't there a way to make it inherit the input signal properties from the parent model?