It seems you are on the right track by trying to document the causal
relationship between your PC service and your injury. That is
probably essential for most claims.
Insurance claims employees attempt to apply existing law to the
information the claimant provides to make their benefits
determination. Claimants can make this process easier for the
insurance provider by understanding the law or policy, to be sure the
claim is presented in a way that clearly falls in the area that is
due compensation. I found it useful to read the actual Federal
Workers Compensation Act.
Asking your congressional representative's office for help should be
a last resort, as Kevin suggests.
I've added a few links in the 'Links' section of this Yahoo group:
1. The Federal Employees' Compensation Act -- This is the legal code
that covers PC volunteers
2. OWCP Home Page -- Division of Federal Employees' Compensation
P.S.: I learned of this yahoo group from a message that someone
posted to my local RPCV group.