add block from custom library simulink

Hi everybody,

i want to build up my simulink/simscape model from matlab command line. The command what i am using at the moment for built in simscape blocks is the following:

add_block('built-in/Scope', [sys '/Scope1'])

When I try to add a block from a custom library like this:

add_block('test_lib/Heat_out',[sys '/test'], 'Position', [(x+offset) y+offset (x+offset)+w (y+offset)+h])

I get the following error: Unable to load block diagram 'test_lib'

Can someone help me with this issue? Thanks in advance!

EDIT: I know how to do it if my library simulink model is in my path. But is there a way of doing it out of the simulink library browser if the library model is not in my path?