I am using Adobe Acrobat Pro XI with an HP Officejet 4315 printer. After installing the drivers from Windows Update (as instructed by HP), when I go to setup the scanning to PDF option I only see WIA 4315 and not TW 4315 available. I am able to scan, but it defaults as a jpeg and always shows me a document that is 8.5 x 14 in size even though the original was 8.5 x 11. This is using Windows 8 64 bit. Is there a way to force the TWain driver through?