Filemaker Go does not do true syncing to either server or Filemaker Pro. You can update data through scripting which can be done with files hosted by either Filemaker Pro or Server.
Tap Open File Browser.. and the tab Local Network Hosts to locate any Filemaker 11 shared file running on a computer with active WiFi. Make sure WiFi is enabled on your IOS device. Then you can click on any file that shows up and that file will act as a served file similar to one being hosted on Filemaker Server. All changes will be saved in the Filemaker Pro 11 file.
To sync changes made on the IOS device while not connected, as mentioned above you will have to script this. Zync has scripts for this if you need them.