Nothing happens... not even if I change the name of the bin file. Maybe a better approach could be to open this bin file and extract this new UI app.
Follow these Steps to install V5S software on V5:
1) Download V5S firmware
2) Rename the COWON_V5S_FW.bin to COWON_V5S_FW.zip
3) If you have Winrar, then use extract here, because it is not possible to open the file. Extracting only...
4) Copy the 3 folders on your SD-Card
5) Put it in the V5
6) Go to the explorer on your V5
7) Copy the 3 Folders from the SD-Card
8) Paste in the root folder of the V5
9) Click yes to all when asked about replacing files
10) The first time it did not worked out, because in this path COWON_V5S_1.01(20110218)_FW\Program Files\CowonApp\MainFlash there is a file called DEFAULT.swf. Copy paste this file into the same folder on to your V5 Program Files\CowonApp\MainFlash
12) Enjoy new UI (only main UI and some new apps in Korean (I do not understand Korean), the other Media-playing UIs are the same)