here is an information from the help:
"... You can create a custom style based on any of the predefined styles by choosing it and modifying the settings on the Customize Style tab. Once you have created a custom style, a new option, called Custom, is added to the list on the Style tab. ..."
so, i dont think we can create/use our own style.
hope SAP (Business Objects) will add it in Service Pack / next release.
maybe someone else have any suggestion/answer/opinion, it will be good for you.
regards,