Hi, and welcome to the forum.
From the manual, page 71-72:
RAM TO ROM COPY
1. While in the SAMPLE MANAGER menu, move the focus to the RAM machine whose content you wish to copy and then press [FUNCTION] + [REC].
2. Choose the ROM slot you want to copy the RAM machine to and then press [FUNCTION] + [STOP]. Since you can’t undo this operation you will be asked whether you want to perform the action or not. Press [ENTER/YES] if you want to proceed with the copy operation.
3. A prompt will ask if you want to "RELOAD SAMPLES NOW?".
4. If you press the [ENTER/YES] button the content of all other RAM machines will be
erased. If you want to copy the other RAM machines as well it is very important that you
instead press the [EXIT/NO] key.
5. When you have copied all the RAM machines you can either press the [ENTER/YES]
key when being asked if you want to reload the samples, or exit the SAMPLE MANAGER.
In either way, all the RAM machines will be emptied.From your description it seems you've copied the pattern data, not the RAM data. You need to go to the the sample manager menu to copy the RAM data.
Hope that helps