Taleo external web service Integration

Hello,

We are trying to built a use case for TALEO Recruiting System integrating with other external system through Taleo Connect Client (TCC). We need to extract some fields from Taleo through TCC and external service will be providing the calculated values for some of the other fields in Taleo. However, the attributes we are looking for, are not visible in the TCC, i.e. Country attribute of the candidate. We are aware of the import and export data process from and to Taleo with TCC but, some of the fields are not available in TCC.

How to use TCC from web service integration perspective? Also, how can we trigger external web services from Taleo system?