I'm working in 5.2, but should be similar.
1. Double click the media event in the Project Overview window.
2. In the Properties window click the Track Media button.
3. Select the Video drop down box and select Replace ...
4. Navigate to your updated file (yes even if it is the same name)
5. Bear in mind that you may well have to replace the audio as well.
I can't find any Global replace or refresh, but at least the above method will keep your menus and links intact.
Hope that helps a little.
COMPAQ something or other with 500Gb Boot Disk, 1Tb external Firewire Disk, 4Gb Memory and a super duper sound card, 19" TFT Monitor etc etc etc
Sony TRV33e : Sony TRV310e : Canon XM2
Sony Vegas Studio editions to v11
Remember, there is always more to learn than there is to teach.