My response:
You'll need to follow the law, and Motion, procedures for obtaining an Order from the court to have your Petition published in a newspaper of general circulation, nearest to where the Respondent was last known to have lived. Do do this, however, you need to attempt "reasonable efforts" to locate the Respondent.
If you know the Respondent's Name and Social Security number, for a reasonable fee, I want you to contact Nelson Tucker of "Attorney Services of Southern California". Go to his website:
http://www.processnet1.com/allabout.htm
He'll help to guide you and to help you to accomplish your duty of reasonable due diligence in locating the Respondent. If he can't locate the Respondent, then he will prepare a Declaration of "due diligence" for you to satisfy the court. Then, you'll be able to file your motion for publication. If he finds the Respondent, then you give Nelson the Petition and all other necessary papers, and he'll have the Respondent "personally served" as is required by California law.
This is not an endorsement. I do not have any financial ties to, or interest in, Attorney Services of Southern California. Nelson Tucker is one of many Process Servers in California, and you are free to choose and use whomever you want.
IAAL