Share data between Matlab and Simulink during runtime of simulation

I have a stateflow model and need to read data from a xml stream over TCP/IP. In Simulink there are receive and send blocks for TCP/IP transmission but Simulink only can handle numeric signals. For that reason I am using a xml parser in Matlab. This works and all needed values from the xml stream are written in the workspace.

The problem: Simulink can read data from workspace but only once the simulation has started. I need get the updated data from workspace during runtime of the simulation. I have already tried: Inport pin, block "From Workspace" and block "Signal from workspace". It is possible to change data during simulation because I tested this with a simple "Const" block.

[Joachim Schlosser]

Did you try to embed your code into a MATLAB function block?