General :: How To Mount Directories Across SD Cards

Okay, this is what I want to do. Under Linux, it would be done via /etc/fstab, but Android has changed some things up.

Certain apps store files and other things on the internal SD card of the RAZR. For example, the Amazon MP3 Cloud player stores all downloaded music files to /sdcard/amazonmp3. There is no way to change this. However, I store all my music on my external SD card. So, what I want to do is create a mount point on the internal sdcard for the /sdcard/amazonmp3 directory that points to a directory on my external sd card (/sdcard-ext/amazonmp3).

That way, when I download music, it will still attempt to save it to /sdcard/amazonmp3 which really is a mount point that points to /sdcard-ext/amazonmp3.

Now, there is an app called FoldersPlug which does this. However, it's not doing it across reboots and it's a little buggy in how it works. I'd rather just fix the /etc/vold.fstab file (if that's possible) to mount my directories for me, but I don't completely understand all the needs to be set up in it.

If I have the following directories set up:

/sdcard/amazonmp3 (this will be empty)
/sdcard-ext/amazonmp3 (this will contain all the files and folder structures that would normally be in /sdcard/amazonmp3)

I want it so that the /sdcard-ext/amazonmp3 directory is mounted to the /sdcard/amazonmp3 directory.

Here is what I see when I run the "mount" command to look at the current mount points that are mounted:

Code:
/dev/block/vold/179:97 /mnt/sdcard/amazonmp3 vfat rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/179:97 /mnt/sdcard/DCIM vfat

[Code]...