For this reason, I define text blocks by wrapping them with the wrap plugin:
Example:
For the pdf generation I use two templates "presentation" and "printing". In the code for the wiki pages I write something like the following:
<WRAP presonly>
Text only in presentation mode
</WRAP>
Text for presentation and printing
<WRAP presnone>
Text only for printing out
</WRAP>
Then in the file "style.css" of the both templates in the pdf plugin I've placed as alternatives these code lines:
/* template for presentation mode */
.dokuwiki div.wrap_presnone {
display: none;
}
/* template for printing mode */
.dokuwiki div.wrap_presonly {
display: none;
}