I have a issue with Caliber Document Factory Word Export

I would need to export a requirement tree into word, but so that the requirement tree hierarchy is reflected in the word heading levels. How to achieve this?

I want the level where I start to export to be Heading 1, and then any sub levels to be word Heading 2, sub-sub levels Heading 3 etc..

Is this possible?

I could not see how from reading the online user guide or the Caliber Samples.