In order to configure Visual Studio to use the Enhanced Client:
Open Visual Studio
Open the Options dialog by selecting the Tools menu and choosing Options.
In the Options dialog, select the Source Control node.
In the Source Control panel, select the SourceGear Vault Professional Visual Studio Enhanced Client in the current source control plug-in drop down box.
To disable IDE Integration, select a different plug-in.
The “Express” versions of Visual Studio do not support source control integration and enabling this option does not override these limitations.