Sony HAP- Z1 ES music server into a DAC... is it possible?


My pal with the Sony server would like to add a fine DAC to his system.  Is it possible to digitally stream music out of the Sony unit into a DAC and then into his preamp?   I can't figure if the Sony has that capability.  If it does, what is the means of the the digital output?  Thanks for your insights.  
whitestix
With the latest firmware upgrade, the Sony can be used with a different dac.  You would use the usb output.  I tried it with a Wyred4Sound dac2 dsd  se dac and preferred the Sony internal dac better. 
Thanks for the insight.  BTW, have you ever heard a different DAC with the Sony or are you content with its internal DAC?   
Just a note about it, not all DACs are compatible with the Sony. Obviously it requires a DAC with a USB input but there are reports of some DACs not working, and it seems to involve a compatibility issue with the DAC's USB receiver circuitry. You should try a specific DAC in combination with the Sony to first see if it works and second to see if it offers any sonic improvement, since the Sony's internal DAC is no slouch and can outperform many external DACs.