You may need to go through this process:
Issue
You want to know how to attach a custom Property Set Definition to pipe or ductwork, so it will be added to the drawing when the part is drawn.
Solution
To link the custom Property Set Definition to the part
On the MEP Common menu, click Content Builder.
Select the pipe or duct you want the Property Set attached to. Click the Modify Part Sizes button.
Right-click on Size Parameters. Click Add.
Select Custom Data 1 and assign a name. (Make note of the name. You will need to make a property definition with the same name later on.) Click OK.
Select Parameter Configuration from the drop-down menu.
Change the Data Storage type for the custom parameter to List. Click OK.
Save and close the part file.
Open C:\Documents and Settings\All Users\Application Data\Autodesk\ABS 2006\enu\Aecb Shared Content\AecbPropertySetDefinitions.dwg.
Open the Style Manager and create a New Property Set Definition.
Select the new Property Set Definition.
On the Applies To tab, select Styles and Definitions. Click Clear All and select Pipe Style.
On the Definition tab, click Add Manual Property Definition. Enter the name of the parameter you created in Step 4 and click OK.
Create any other Property Definitions you want in the Property Set.
Save and close the drawing.
Open a new drawing.
Draw the pipe type you modified in Step 2.
Right-click on the pipe. Click Properties.
In the Properties dialog box, click the Extended Data tab. You will notice that the Property Set is attached to the pipe.
The Property Set is style based and cannot be changed in the Properties dialog box. To change the data in the Property Set, follow these steps:
Right-click the pipe. Click Edit Pipe Style.
In the Pipe Style Properties dialog box, on the General tab, click Property Sets. This will open the Edit Property Set Data dialog box.
And why doesn't MEP work right with Architecture???
The Same reason MAP inside Civil 3D doesn't work with Civil 3D objects. The Subscription program does NOT encourage Autodesk to test their products for interoperability. They do not care if their products do not work with each other. They have your money, and thus NO incentive to test to see if things like DYNanmic input has adverse affects in the vertical applications when the DYN setting suppresses the vertical application prompts. When we all get together and stop buying in to this subscription nonsense, only then will Autodesk be motivated to fix these issues because they wont be selling any software for 6-9 months if we all just hold out, and say NO. No new version , NO subscription until you fix this stuff and give them your list.