Just cash it in. The Provident fund is really nothing more than a savings account which is registered in the Isle Of Man. I believe you can also keep it running after you leave EK so have the option of drip feeding it back to the US as and when.
Why don't you contact Mondial and ask them. It's free and you get 2 consultations per month. I'd also back that up with an independent financial advisor/accountant who is expert on US tax law.
Harry