Specifying default installation drive in .pkg file

in the .pkg file , if we want to select the installation drive (Phone memory or Memory Card)at runtime , we put a "!" instead of the drive letter. If we dont want to show the drive selection dialog during installation, we can specify the drive letter in which we want to install out exe instead of the "!" letter. Like this:
"C:\S60\devices\S60_3rd_FP2_SDK\epoc32\data\z\resource\apps\MyApp.rsc"-"C:\resource\apps\MyApp.rsc"

But in Visual Studio 2005 , this solution does not work if we build the .SIS file using the VS2005 IDE. So, to make this thing work we have to go to the "sis" folder under the project folder and run the following command:
makesis MyApp.pkg

Then this thing will work. So, what we need to do when we are using the VS2005 as development environment is to rebuild the solution and then run the above stated command. Building the SIS file using the IDE wont work.