We do not support predefined word-like styles currently, but we are planning on including them at some point, hopefully in 2011.Q1.
I have prepared a sample demo, which shows how you can define and set a style on button click. When there are selected parts of the document, the changes are applied to them. If the selection is empty, the changes are applied to the whole paragraph (like Headings work in MS Word).
Note that there is a small bug with the Background property of the paragraph and you need to set it, otherwise a NullReferenceException will occur. This will be fixed in the next release.
If you have other questions, do not hesitate to contact us again.
the Telerik team
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