This can be done through either the SDK symbol.dll and symbol.barcode.dll or through a change to the registry file. If you have an existing app and are moving from MC70 to MC75 then a registry change is the best way to go thus ensuring no changes are required to your application codebase.

Step 1: paste the following into a .REG file and copy to the device /Application using activesync.

 [HKEY_LOCAL_MACHINEDriversBuiltInBarCodeReader]
"Index"=dword:00000001
"Order"=dword:00000006

[HKEY_LOCAL_MACHINEDriversBuiltInBarCodeReader2]
"Index"=dword:00000002
"Order"=dword:00000005

Step 2:
Double click on the file once on the device, press Yes.

Step 3:
Cold boot the device.

Note: you may also update the registry hive through XML provisioning.

Enjoy,
Shadow