Compile 64-bit SQL Server Driver for PHP - php_sqlsrv.dll

Follow the instructions from  README.TXT of the source code, (http://sqlsrvphp.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=31762)
I can compile 32-bit php_sqlsrv.dll in Visual Studio 2008 easily. But got some errors when I try to create x64 php_sqlsrv.dll.
I can compile x64 PHP 5.3.1 from source code with php_curl, php_zip etc .  without any problem.
when compiling 32-bit php_sqlsrv.dll, in config.w32 ,  need to  remove this line
ADD_FLAG( 'CFLAGS_SQLSRV', '/WX' );  
/WX  flag is not necessary,  makes some trouble.
My machine configuration:
MS Windows 7 64-bit
MS Visual Studio 2008 Professional

If someone has a successful story in x64, Please give me a post.
thanks a lot.