To insert an rtf document in a merge field use the "document(rtf)" modifier:
When inserting an rtf document, the document must go at the same level as the paragraphs, this means that if the merge field is in the middle of a paragraph:
Some Text Before «Product.Doc(document(rtf))» Some text after
It will become:
Some Text Before
My sweet rtf document
has some content
Some text after
As a special case, if you don't have any content on either side:
«Product.Doc(document(rtf))»
It will become:
My sweet rtf document
has some content
Having only text before or only text after, will result in a blank paragraph on the other side, such as:
Some Text Before «Product.Doc(document(rtf))»
Will become:
Some Text Before
My sweet rtf document
has some content
{quote}
Rtf documents maintain their own formatting, so if there is some bold text, or a right-aligned paragraph in the rtf document it will maintain that formatting. This includes the default font for the document, which may not match the default font of the template.