Import table from "usr" layer to "cus layer.

I want to know about the concept of import table from usr layer to its upper cus layer.

What I do is this:

1. Create a table on the usr layer (TestXX, with single field : XX).

2. Export the table from usr layer.

3. Open a new AX program on cus layer.

4. Import the table in the cus layer.

5. Delete the table from the usr layer.

6. Close the AX on the cus layer, and oppening it again.

What I see is that the cus layer has the new table (only cus layer), but when I want to see the properties, when standing on the testXX table, I see that properties are disabled, and there is no ID.

(I did synchronization, but in vain).

What is wrong of above, and how can I move table from usr layer to cus layer (while I don't want loosing data, if any on tableXX)?

Thanks :)