How to determine the keyword for existing testcase custom categories within a RQM Sandbox Project

Within the Jazz Sandbox .. I have created a few new test case categories ( eg. "Program Name" , "Application" ).
I have Test Cases in Excel that I will be importing but I do not know how to reference the new test case categories fields above.
I have searched within the forum and have read the following:
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If the keywords is existed in the QM server, then you can by follow steps:
1, get the existing keyword's internal id by REST API, keyword's internal id looks like "urn:com.ibm.rqm:keyword:3"
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When I posted the below (using Mozilla Poster) for against the Jazz Sandbox:  
https://jazz.net/sandbox03-qm/service/com.ibm.rqm.integration.service.IIntegrationService/resources/keyword

.... I received  :
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<?xml version="1.0" encoding="UTF-8"?><feed xmlns="http://www.w3.org/2005/Atom"><title type="text">keyword ATOM feed for all project areas</title><id>https://jazz.net/sandbox03-qm/service/com.ibm.rqm.integration.service.IIntegrationService/resources/keyword</id><link href="https://jazz.net/sandbox03-qm/web/console/" rel="alternate"/><link rel="self" href="https://jazz.net/sandbox03-qm/service/com.ibm.rqm.integration.service.IIntegrationService/resources/keyword"/></feed>
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Given that my command did not include my "project" and "testcase" area ... I was not expecting a correct response. 
Question: What REST API command can be used to determine the keyword for existing testcase custom categories within a RQM Sandbox Project ( ps. I am assuming using Mozilla Poster is also ok) ?

Thanks in advance ..