There should be an option to print grayscale. How you do this depends on which RIP you are using, look it up in the online help. The only problem with grayscale is that you get a noticeable dot pattern with only one head printing. Your best option is to adjust the file. Good luck.
In the last tab in Pre-Flight, Print, there is a button labeled Print Setup. The last tab in this dialog box is Output. There will be a setting for Grayscale there.