Had a quick look at the requirements for this and it might be a bit more complex than you would initially imagine (at least it was for me!).
Given that you've attempted to mirror the Incident object, I'll use that as a comparison.
Let's take a look at the Incident field 'Status' - you should notice it is validated. If we then take a look at the associated ValidationObject, IncidentStatus, we can see there are fields here to configure the progress bar, aptly named ProgressBarPosition (which itself is validated).
Now, as you'll know, in order to show a record on the 'My Items' workspace, we need to create a relationship between Frs_MyItem and the relevant BO. As you'll also know given this question, there is something else happening to configure the record in the MyItem context. With that in mind, take a look at the quick actions of Frs_MyItem. Now we're getting somewhere.
Here is where the bulk of the updating appears to take place - but what triggers that I hear you ask... If you look at the Incident business rules, there should be a triggered action there called 'Update My Item'.
Now, Change is a bit of a beast. So without looking further into it, I couldn't say what exactly needs to be done but essentially, there needs to be a reference to the desired progress bar position which is then updated once the MyItem (Change) record is created.
Hope this helps shed some light, John