How do I edit irrigation symbols?

[Doug L]

How do I custom edit irrigation symbols? I've duplicated the library file (to create Rainbird heads from the default Toro), went to the resource browser, right clicked an irrigation head, clicked Edit, clicked Edit 2D component, which brought up the Edit Symbol window. After I changed the Head Scale Factor in Object Info, it appears that I can only add to the symbol graphics (such as tick marks to graphically differentiate between 10, 12, and 15 series heads). Here is what I would like to do:

1. Change the head symbol from a circle to a square for all the strip heads.

2. Move the end strip head symbol from the center of the spray pattern to the end of the pattern where it actually belongs.

3. Create Rainbird right corner and left corner strip heads.

It appears that I can ungroup the head object, with a warning "Are you sure you want to ungroup high-level objects?" After clicking Yes, I am finally able to fully edit the symbol, but now, all the head's object data is gone. How can that data be added back in? (I see that Modify/Create Symbol will create a new head, but without the original irrigation object data).

Thanks.