Pierpaolo,
QRecall 1.3 has a number of new scheduling features in the works that I think will address your situation. Specifically, a new event schedule that will run an action when an application launches or quits. This way, you can simply schedule your capture action to run whenever DevonThink quits.
The next version will also have some scripting options that I'm looking for users to evaluate.
A beta of QRecall 1.3 should be available for testing by early September.
pirem71 wrote:Another separate feature request: menu bar drop-down list is now displaying next scheduled action; it would be nice if it could show the scheduled time of that action (as done in Actions window).
This is already on the to-do list.