How can I fire the 'create.task' action when user drops a custom element in the canvas?

I made a schema so it is easier to explain what I’m looking for.
The user can choose among a number of available tasks (each one running different operations in the back-end).

1- the user drags and drops a task in the bpmn-jd dropping zone

2 - the drop event is fired and a new bpmn-Task is drawn

3 - firing the drop event also redirect the user to a webpage where it is possible to set input/output files.

4 - the tool reads out the in/out infos and dinamically adds as many DataStoreReference (DSR) objs as the in/out files reqiured by the Task selected. The input DSRs connect to bpmn-task with a → arrow, the output DSR with ← arrow.

5- a new Task is dropped and the user is redirected to set in/out files for the current Task (n)

6 - the tool adds a bpmn-task just under the (n-1) DSR output, if one of the (n) input files is chosen among the (n-1) outputs.

And so on……
my_tool
Hope this is clear enough…
Thank you!!