It seems the hold button has no entry in the parameter hook list…
To control the hold button, i guess you have to use Taktiks secret parameter trick
<?xml version="1.0" encoding="UTF-8"?>
<filterdeviceclipboard doc_version="0"><br>
<deviceslot type="RepeaterDevice"><br>
<isactive>true</isactive><br>
<isselected>true</isselected><br>
<selectedpresetname>Init</selectedpresetname><br>
<selectedpresetismodified>true</selectedpresetismodified><br>
<ismaximized>true</ismaximized><br>
<mode><br>
<value>2</value><br>
<visualization>Device only</visualization><br>
</mode><br>
<divisor><br>
<value>0.75</value><br>
<visualization>Device only</visualization><br>
</divisor><br>
<hold>true</hold><br>
</deviceslot><br>
</filterdeviceclipboard>