detecting when a form is closed

Hello,
I am trying to automate some tasks for IDX export in Allegro in skill
To do this, I am calling the "idx out" command which brings up the IDX Export form.
I can automate to fill in the form and 'execute' it.
The problem now is, that the form itself is kind of wizard style and has multiple screens the user interactive has to confirm (which is fine).
The wizard then comes back to the initial startup form and once the user closes this form then I would like to run a post processing on the created data.

The issue I currently have is that I cannot detect once this form is closed. I really have no other means than calling the "idx out" command in Allegro.

Example Sequence:

- call my registered command
- the command is calling axlShellPost("idx out;_setwindow form.idx_out;");
- form is coming up and with axlpostShell("fillin form....") I fill in data like the filename
- axlShellPost("FORM idx_out execute") then executes the form
- now the idx_out form is changing to the next page and user does something.
- when he confirms, that the form is coming back to the initial state
- user then closes the form
- After this, I want to execute some prostprocess, so I would need to know that the form is closed

>>>>
axlShellPost("idx out;_setwindow form.idx_out;");
axlShellPost("FORM idx_out execute");
axlShellPost("now do the job"); --> this line is executed directly after the previous one but it should execute after the idx_out form is closed
axlUIConfirm("Push Data done");

unfortunately it seems that the form is asynchronously, which means that my postprocess code is executed directly after I do the axlShellPost("FORM idx_out execute")

Any idea on how to achieve this?
Is there a way to find the idx_out form and potentially listen on the dispose?

btw, all of this is done in a callback function as I added an additional form for our purpose