Since getting a 2GB RS-MMC card for my 770 I have been thinking how nice it would be to open the video player, image viewer, audio player etc and actually have it pointing at a folder that contains content. You see I don't store any media on the 770. I'd rather leave that space free for future application installations.
Fortunately my problem was very easily solved thanks to the nature of Linux.
If you plan on doing this, I recommend either cutting and pasting the commands from the 770's web browser into the "X Terminal" app or SSH'ing into the 770 and pasting them in from your desktop.
First, check that you don't have any files in the default directories, they will not be deleted but you will no longer be able to access them via the file manager or most applications. Then we must make the directories on our Memory card which we plan to store our media in:
mkdir /media/mmc1/Documents
mkdir /media/mmc1/Images
mkdir /media/mmc1/Sounds
mkdir /media/mmc1/Videos
You can obviously call them as you wish but be sure to change them in the code below. Now we symlink the old directory file names (after renaming the old directories)
so as to have them lead to the directories on the memory card.
mv /home/user/MyDocs/.documents /home/user/MyDocs/.documents.old
ln -s /media/mmc1/Documents /home/user/MyDocs/.documents
mv /home/user/MyDocs/.images /home/user/MyDocs/.images.old
ln -s /media/mmc1/Images /home/user/MyDocs/.images
mv /home/user/MyDocs/.sounds /home/user/MyDocs/.sounds.old
ln -s /media/mmc1/Sounds /home/user/MyDocs/.sounds
mv /home/user/MyDocs/.videos /home/user/MyDocs/.videos.old
ln -s /media/mmc1/Videos /home/user/MyDocs/.videos
Then, we load up an app such as the audio player or video player and enjoy 
