specifying only some options?

SplashImageOn ( "title", "file" [, width [, height [, x pos [, y pos [, opt]]]]] )

I only want to specify certain parameters like the optional flag.  I would like XPOS and YPOS to remain default.  Like this....

SplashImageOn ( "", "C:\image.jpg", 200,  100, "", "" , 1 )

I have tried it several different ways.  Commas only, quotes, brackets, it just doesnt seem to work.

Any help?