From the "Room Items" menu, Custom Item(s) can be saved to the user's "Uncategorized" My Catalog.
The Procedure
1.
Enter the name of the Custom Item(s)
2.
Click the "Take Thumbnail Image" button
3.
Adjust the cropping area of the Thumbnail Image and click the "Crop the Image and Save" button
4.
Confirm that Custom Item(s) are saved in "Uncategorized" My Catalog