¿how to post a message with attachments using jive api?

I finally managed to develop a JAVA method that using the REST API2 from JIVE can create discussions with an attachment.

First of all we need to upload the file to our JIVE instance in order to get a valid URI to reference when creating the discussion, see REST Reference : Attachment Service for more info about it, after sending a request to this attachment service it returns the valid URI as a header of the response now this URI will be the value of the "attachmentURIs" parameter that will be send when consuming the Discussion REST service

To create the discussion we use the Discussion REST service (see REST Reference : Discussion Service), we can send the basic arguments that are: subject, question, html and attachmentURIs; this last parameter is where we reference the URI retrieved from the response when consuming the attachment service. You need to know the  ID of the group or space where you want to create the discussion, for that you can use the GET http action over the discussions or spaces service, for example: http://192.168.0.15:8080/api/core/v2/groups?offset=0&limit=25 will return in the response all the info about every group from the jive instances referenced in 192.168.0.15:8080, see REST Reference : Discussion Service and REST Reference : Space Service for more information about the URL structure and other stuff.

Finally our response will look something like this:

POST /api/core/v2/groups/1004/discussions HTTP/1.1

Authorization: Basic YWRtaW46YWRtaW4=

User-Agent: Java/1.7.0_03

Host: localhost:9696

Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2

Connection: keep-alive

Content-type: application/x-www-form-urlencoded

Content-Length: 64

&subject=Testing rest services&html=This is a test&attachmentURIs=http://1923.168.0.15:8080/api/core/v2/attachments/6661&question=true

When you check your JIVE instances you will see the new discussion created in the group with id 1004 for this example:

IMPORTANT: Every POST request you send to consume any REST service from the JIVE API2 must has in its header the basic authentication with the user and password of an authorized JIVE user for this operations. You can see the java code attached in order to get a better idea (HttpReqSender.java file).

Thanks to everyone that helped me with advice and documents