[plt-scheme] Timespans

After looking over SRFI 19: Time Data Types and Procedures, I noticed
that it was sorely lacking in timespan manipulation functions. For
example, if I have a time span of, say 45932 seconds, there is no easy
way to get it in a format like days.hours:minutes:seconds (12:42:32),
etc. Am I missing something?

For reference, I am used to the .NET TimeSpan structure documented at
http://msdn2.microsoft.com/en-us/system.timespan_members.aspx

Thanks for your help.

-- 
Chris Warrington <chrisw at rice.edu>

"Time is an illusion. Lunchtime doubly so."
-Douglas Adams