For Baan under Unix there should be no problems at all. The bar codes are integrated the standard way, using a shell script (documentation on request). Trigger words for rules are normally found.
For BWPRINT running under MS Windows, the situation could be for Trigger Words different. They are maybe not found, as the driver generates the text fully graphically. Anyway first try the standard rules method, and if it really doesn't work then use this work around: Setting the width parameter in the font description to 0.