to_json(now()) result doesn't have 'T' separator

# select to_json(now());

             to_json

---------------------------------

 "2013-12-20 15:53:39.098204-08"

(1 row)

I'd like to see it output "2013-12-20T15:53:39.098204-08" so it's interchangeable with more systems. 

http://en.wikipedia.org/wiki/ISO_8601#Combined_date_and_time_representations says 'T' can be omitted "by mutual agreement". 

I'm working with javascript/json systems that expect the 'T' to be there however, so there's no mutual agreement happening.

Thoughts? I know I can hack around it by specifying my own date format, but I'd really like to be able to use row_to_json and other functions without specifying custom date formats everywhere.

Joe