Mirroring of Sybase devices

Hello guys.

We use disk mirror to change the physical device or from file system to raw device (and vice-versa).

Another DBA said we could not mirror a device that was already mirrored in the past.

For example: I mirrored Dev1 to Dev2 and now I need to mirror Dev2 to Dev3. He said it would not work.

It doesn't make sense to me, but I would like to have confirmation it would be possible.

Thanks in advance.

Sergi T.