I have been struggling with the same issue for some time now,
same version of RoboHelp with Word 2003. Can't say I have come
across a good solution yet. However, there is one solution that has
helped me - makeing sure the modified template is applied to each
document in the project. From the Word help file:
On the Tools menu, click Templates and Add-Ins.
Click Attach, and then select the template you want.
Click Open.
Note To use styles from the newly attached template, select
the Automatically update document styles check box in the Templates
and Add-Ins dialog box. Click OK.
Repeat this for each document.
The trick may be creating the original template file. Once I
got mine created the way I wanted, I copied it to another folder
for safe keeping.