DoFieldExchange- how to modify/retrieve values from bound member?

I have a CDaoRecordSet derivative. In the DoFieldExchange() method, I want to be able to take the value in a bound data member (of type CByteArray), and transfer it's data to a non-bound data member of type CMap(and retrieve it's data to store in the CMap). I'm looking at the value of pFX->m_nOperation to determine the operation being performed. Currently if it is equal to CDaoFieldExchange::StoreField, then I transfer the data in my CMap to the bound member. If pFX->m_nOperation is equal to CDaoFieldExchange::LoadField, then I retrieve the data and store it in my CMap. When saving the data, the bound member is NULL.

What am I missing?