I would think you probably aleady have it on your device but it might just be disabled.
Check this registry value:
HKEY_CLASSES_ROOT\CLSID\{62B00599-25D2-4e09-8C48-03BF26DB8517}\IsSipInputMethod]
"Default"="1"
If it is set to 0 then change it back to 1. Hope that helps!