Hi,
In the link:
http://msdn.microsoft.com/en-us/vsts2008/aa718949.aspx
In the title "Updating GAX", you will be able to read that you don“t need to do nothing special to migrate the guidance solution.
With regard to the problem with the register item in the context menu, have you enabled the "Guidance Package Developer" ?
The option is in the VS menu: Tools -> Guidance Package Manager.
In the form, you need to click the button "Enable / Disable Packages".
I hope that this will help
greetings
Leandro Tuttini