When using a stored Procedure to insert a new record. When is the acquisition of the new identity key (AutoNumber) is happening after the insert is committed. Is it part of the same transaction or not?

Is it possible to read the a return parameter of the stored procedure (insert procedure)?

The acquisition of the key depends on the setting in Mandatory keys dialog.
Identity=No: GeniusConnect will run the statement before insert
Identity=Yes: GeniusConnect will run the statement after insert

GeniusConnect can't use return parameter, your SP must return a result set with 1 row/value.

If you are using auto identity value you can use statements like select @@identity (SQL Server).

The statment to get last identity depends on your DB system.