I suggest that you use the new REST APIs instead of the XML or SOAP APIs. The REST APIs are the future of API access on ClearPass, and the API docs are built-in. Browse to https://<CPPM>/api-docs. I've also attached a rough draft of some notes that should help get you started.
As an example, here's the data from a single guest account:
{
"id": "3001",
"username": "anonymous@anonymous.anon",
"start_time": 1395854644,
"expire_time": 0,
"sponsor_name": "admin",
"sponsor_profile": "1",
"enabled": true,
"current_state": "active",
"notes": "Just some notes",
"visitor_carrier": null,
"role_name": "[Guest]",
"role_id": 2,
"email": "anonymous@anonymous.anon",
"visitor_company": "anonymous",
"do_expire": "0",
"expire_postlogin": "0",
"sponsor_profile_name": "IT Administrators",
"visitor_name": "anonymous",
"source": "create_user",
"remote_addr": "199.127.104.10",
"simultaneous_use": "0",
"create_time": 1395854588,
"expired_notify_status": "1",
"_links": {
"self": {
"href": "https:\/\/cppm.anonymous.anon\/api\/guest\/3001"
}
}
},