Custome Outlook plugin not displaying on Outlook.?

I have develop one Outlook Addin/Plugin using VS-2008 and OUTLOOK VSTO 2007, and I have created a setup project for that to install the Plugin on User system.
 
it all work good on Windows 7 + outlook 2010
but when I try to install it on windows XP + Outlook 2010 then it will not working properly.
 
means when I goes for win xp + 2010 it will not load the plugin.
for loading the plugin on outlook I have set the some registry value to addin on registry editor. one of the value if load behaviour is set to 3 for normal loading. but when I use win xp + 2010 it will automatically set to 2 which means inactive the plugin. I manually set it to 3 then try to restart the outlook but it will again set to 3.
 
so please provide me suggestion.