database reading through voiceXML

Hi,
Are there any tags in voiceXML that can make program read data from database by generating the queries dynamically?
If yes then what are those tags?
If no then is it possible to have customized tags (say "dbread") in voiceXML? viz.
<prompt>
Your account balance is <dbread table='account' field='balance'/>
</prompt>

Is this feasible? OR we have to always submit to next asp or jsp or whatever and generate the vxml with account balance information dynamically?
If it is feasible then...
do the vxml interpreters available today can support customizable tags? Like if a custom tag is found the interpreter should hand over the control to the application to take necessary actions.

Regards,
Shridhar