Check out this blog post from Brian Dukes at Engage Software about this very subject.
Editing .SqlDataProvider scripts within Visual Studio
By simply adding a .sqldataprovider key
to the correct location and giving it
the same value as the .sql key,
everything magically works as
expected.
The key to create is
HKLM:\SOFTWARE\Microsoft\VisualStudio[version]\Languages\File
Extensions.sqldataprovider where
[version] is 7.1 for Visual Studio
.NET 2003, 8.0 for Visual Studio 2005,
etc. Those are the two versions I
updated, so those are the two I'm sure
of. You should be able to find other
versions without too much trouble. If
you're into PowerShell (I'm getting
there), here are the four seperate
commands to run in order to add this
functionality to those two versions of
Visual Studio.
Commands for Visual Studio 2008
New-Item -Path 'HKLM:\SOFTWARE\Microsoft\VisualStudio\9.0\Languages\File Extensions\.sqldataprovider'
set-itemproperty -Path 'HKLM:\SOFTWARE\Microsoft\VisualStudio\9.0\Languages\File Extensions\.sqldataprovider' -name "(default)" -value "{FA6E5E79-C8EE-4D37-B79A-5067F8BD5630}"