As far as I know this can not be done. Yet if you want to have custom layout of IW44 you will be required to go for Module-pool programming through an expert ABAPer. In this not only Confirmation text ypu can re arrange whatever fields you want of IW44. The logic will be : The program will pass the values from your custom screen to the respective fields of IW44 and execute. So that's from my side.
Jogeswara Rao K