You can use styles that are not defined in the document template as long as they are provided in the stylesheet. You must type the name of the style in the element's property view. When the output is generated, the style you defined is used. If a style with that name is not found, no style is applied to that element.
For Microsoft Word output, if a style with the same name as a style defined in the document template is present, the stylesheet style is used. For HTML output, you can manually remove the Rational Publishing Engine style from the generated stylesheet so that the provided stylesheet is used.
If a style is applied to a template element that also has values set for individual formatting properties, the element's changes overrides the styles if such an overlap exists.
You can use any name, except the numbers 1 through 9, for styles. These numbers are reserved style names, which are matched to heading styles in the output formats. The name 1 is translated to Heading 1 for Microsoft Word output and H1 for HTML.