storage api file upload

Hi,
I am trying to upload a csv file through tcl program. i couldn't succeed.
as the enctype is multipart/form-data
i did http post like this

--NEXT_PART_1201367828.1640
Content-Disposition: form-data; name="content"; file="test.csv"

1,2,3,4,5,6
2,3,4,5,6,7
3,4,5,6,7,8
--NEXT_PART_1201367828.1640--

the response from zoho server is

{"response": {"uri":"/api/private/json/uploadbook","error": {"code":2831,"message":"The parameter [content] required for processing this request is missing."}}}

could someone give a hand?

thanks
Sasi