Using Task Workflow

We want to create a Task called Warranty Claim Approval and attach a workflow to it to notify and request approval of the calim based upon the $ value of the claim.

We see the Submit Workflow button and find it uses the Standard Service Task manager and the function JTF_TASK_WF_UTIL package.

We would like to use this but don't know where to find the referenced function to add coding, notifications, etc.

Or would we better of creating our own workflow?