How to define Link List

Dear sir or madam,

I am using the app "Manage Supplier Line Items" (App-ID F0712).

As I select one journal entry via its link a window opens up offering "more links" to this entry.

My question is how to define new links in this list ("Define Link List") to jump to an external URL?

Is it possible to call an URL with parameters from this mask/app for example the supplier-number or the journal-entry-number?

Thanks in advance, Marc