In the Joomla template each module position is tagged with following tag :
<jdoc:include type="modules" name="xxx" ... />
where xxx is position name.
To exclude specific module position from page caching it is necessary to mark this position in template source (mostly index.php) with special JotCache HTML comment tags - see example :
<td>
<!-- jot user2 s style="xhtml" --><jdoc:include type="modules" name=user2" style="xhtml" /><!-- jot user2 e -->
</td>
Text in the marking tags is separated with exactly one (1) space starting with word jotfollowed by name_of_position jot_flag params
where
name_of_position - name of position as it is used in jdoc tag
jot_flag - 's' for start marking, 'e' for end marking
params - any kinds of jdoc parameters separated with space character
The modules I require to be non-cached are located in module position