It works for me sending an email from a gmail account to my server gives this:
.... and an email sent from my server to a gmail account:
X-Spam-Status: Yes, score=7.829 tagged_above=-10 required=5
tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1,
FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, MIME_HTML_MOSTLY=0.428,
Did you follow the instructions in the wiki article? You're going to have to give some details of the exact changes you've made to your ZCS server and what your SPF records are and if you've tested them.
Received-SPF: pass (google.com: followed by the correct domain and permitted sender IP