Question Internal and external SD card

Hi

Have a basic i9000 or maybe just general android question.

The i9000 has an internal SD card. I think it's mounted as /sdcard/sd.

I created a few files under /sdcard/sd before i put in an external SD card.
The problem is after inserting the external SD card. The /sdcard/sd is now showing contents in the external SD card. I couldn't find the files in the internal SD card until i unmount the external SD card.

Is this how android should work? Can i mount the external SD card with a different name (eg /sdcard/sd2) so that I can access both the internal and external at the same time?