retrieve InDesign server warnings

Hi,

I am using InDesign Server via its exposed web service to convert an indesign file to PDF.

If there are missing fonts or outdated/missing links, the indesign server console will print out warnings.

Example:

11:21:15 WARN  [font manager] Missing Font TT Slug OTF

The problem I have is that the WS API call does not return these warnings, as far as I can tell. It just converts the PDF using replacement fonts.

Is there a way for me to get this warning information back from the server or doing a preflight is the only way ? 

thanks

Cristian