I would recommend you go back to your previous question and follow the advice regarding data logging. My comment regarding "mask parameter could be a workaround" is really for the sake of argument. Your approach of putting a "To Workspace" block inside a customized library block is non-typical. It can be made to work with mask parameter but it is a stretch.
However, to prove it can be done, I'll show you the method here. Still, I strongly recommend that you use other data logging method. The worst case, is that you can choose not to put the "To Workspace" block inside the customized library block. Rather, you can put the "To Workspace" block outside of the reference block in the model.
Assume you added a mask parameter called 'VarNum' which is an 'edit' type, and the name of the "To Workspace" block inside is still called "To Workspace", you can add the following line in the "Dialog callback" of the mask parameter 'VarNum'.
set_param([gcb,'/To Workspace'],'VariableName',['A_Out',get_param(gcb,'VarNum')]);
