boundary problems of 2-D convolution block in Simulink

Hi experts, recently I'm running simulation of pattern dynamics for the Brusseltor model in the simulink environment. To process 2-D convolution I simply picked up 2-D convolution block. But the results seems strange. My questions are

1. How to setup different boundary conditions ? Matlab built-in conv2() allows easy setup boundary conditions for either wrap, zero-flux, etc. How shall I realize them in the 2-D convolution box ?

2. How to let 2-D convolution block accept floating points ? Configuration of 2-D convolution box allows various fixed-point modes, but how shall I adjust it so that the convolution of matrix will have floating points ?

Many thanks Kyle