We have done this by using an external task to call a bat file (we use a windows environment). The external task is then called from an EDQ Job.
The bat file contains a SQLPlus call that executes the SP:
sqlplus -l [USER]/[PWD]@[Connect_Identifier] @"[FileName].sql"
Hope this helps
It is also possible to do this using a custom processor in EDQ. The processor needs to do something very similar to the external task above (opens a DB connection, authenticates, runs a stored procedure).
If you need this, please talk us through the use case so we can determine if it is the best fit. In some ways, an external task is better as logically a stored procedure call is normally divorced from any process logic in EDQ.