Printing to PostScript - Clean7Bit or Binary

When we "print" an .indd document to PostScript using InDesign CS3 (desktop version), the resulting file's DataDefinition is always set to Clean7Bit. However, when we call the Java InDesign Server API (using InDesign Server CS3) to print to PostScript, the resulting file is either Clean7Bit or Binary. It is not consistent. Is there a value we can set to always guarantee the resulting file is Clean7Bit?

Thanks for your help!
Jennifer