Here is something I am currently exploring: MvParts. (As you've probably noticed since this is the second post in a row concerning them). I am still in the learning process, so this is what I have found thus far. This is based off of having connectors already set up in an existing MvPart.
MvPart: Editing Connectors:
Open up a blank drawing and go to modelspace.
Click on CAD Manager/Content Editing/Content Builder.
Surf to the location of the MvPart that you want to modify.
Select it and then click on the "Modify Part Size" icon on the far right side.
(It's about the 5th button down)
When you get the new pop-up window click on the "Connectors" tab at the top.
Right click on the "Connector 1" (or whichever connector you want to edit) that is under the specific block that you need to edit.
Click on "Edit Placement".
You will now be inside of that drawing and have a new palette show up call the "MvPartBuilder-Connector Editor".
If you know the actual point locations you can drop them in at the bottom of this new palette under the "Connector Geometry" section, under the "Position" subsection.
OR I believe you can click on the ellipse "..." button and physically select the locations.
Once you're done with that hit "OK" on the "MvPartBuilder-Connector Editor".
This will take you back to the MvPart Builder pop-up.
If you need to edit other connectors you can do so by clicking on them and going through the same process.
Click "Ok" and this will exit you out completely from the Content Builder.
You may have to save and regen your catalog; and you may have to close completely out of ABS (and the others whom you want to see your changes) and then open ABS back up.