I'm trying the SSML example from mod_cepstral wiki
 
<action application="speak" data="cepstral|david|<prosody volume=13>Thank you for holding</prosody>"/>
 
but the voice doesn't say the sentence but says something like "slash blablabla...".
 
Any idea why I can't embed SSML tag in the cepstral sentence ?
 
Thanks