Problem with "Find update" button in the add-ons manager

Hello,

I have a problem with “find update” button for extension updates.
Actually, the button “find update” (when you right click an extension
in the add-ons manager) appears disable, whereas I have well in my
install.rdf put the following lines:

<em:updateURL>http://www.mywebsite.com/update.rdf</em:updateURL>
<em:updateKey>…my_key…</em:updateKey>

You can see a printscreen here : [url]http://img23.imageshack.us/img23/1306/updatesba.jpg[/url]

Notice that I have installed my extension using the register, by
entering a new string value in HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla
\Firefox\Extensions
([url]https://developer.mozilla.org/en/[/url]
Adding_Extensions_using_the_Windows_Registry)

I have noticed that if I install the extension by placing it in the
folder
“C:\Documents and Settings\Dave\Application Data\<vendor>\Extensions
\<appid>“ the “Find updates” button appears enable.

Why is this happening? Have someone also experiment this issue? How to
solve it?

Thanks in advance for your help.

Thanks for your answer Neil,
[color=blue]
>I don't think Firefox tries to update extensions installed using the registry.[/color]
Thus, there is no way to update extensions that have been installed
using registry?

Thanks in advance.