need help passing params to DOS cmd

[VBuild_Rookie]

I have a step that runs a dos cmd in it I have

%DOSCMD% "C:\My Projects\Sykes Newton\Enterprise\Version 1.0\ConfigManger\ConfigUpdate.exe" "/
configuration/appSettings/add[@key='DatasourceConnection']/@value" "initial catalog=PG_Newton;data source=SQL1;u
ser=USER1;Password=USERPWD1;Persist Security Info=False;" "C:\My Projects\Sykes Newton\Enterprise\Version 1.0\Set
up\Source\Server\Web\RemotingServices\Web.config"


I get this error
Building project step 'Remoting Services - Change the DB Name'...
Error expanding macros in property command: C:\WINDOWS\system32\cmd.exe /C "C:\My Projects\Sykes Newton\Enterprise\Version 1.0\ConfigManger\ConfigUpdate.exe" "/
configuration/appSettings/add<Error at Line 1, Column 5 (Syntax error)
Code: key='DatasourceConnection'>
Build ended.


but I can run the exact command in the dos window......any ideas ??