The simplest effect you can emit from custom content is generated text. To automatically insert text before or after your element contents type the required text into the pre-content or post-content customisations. Any amount of text, from single characters to whole paragraphs, can be added this way.

If a section number needs to be printed in square brackets, then type [ into Pre content and ] into Post content of the section number tag mapping. The construction <secnum>11B</secnum> in the document will map to [11B] in the output.

If a part number is always preceded by "Part — " then type Part &mdash;<space/> into the Pre content field. Using <space/> instead of a space character (at the end of a line) ensures that the space is clearly visible when examining or editing the custom content.