I did try the native client a while ago and I didn't get it to work, so I got the mssql extension working instead.
Have you looked into the
mssql[
^] extension for PHP? The alternative is
FreeTDS[
^].
I only have experience connecting to an MSSQL DB on an IIS server with the mssql extension. The only (major) problem I had with it was that a couple of dll's were missing from the
C:\Windows
folder, ntwdblib.dll in particular.
php_mssql.dll
was also missing from
C:\inetpub\php\ext
folder. After I put the dll's in the right place all I had to do was update my
php.ini
file an it worked.
Hope that helps.