Unfortunately it is not possible to lookup a value in a parameter map using a query item as the key such as you are trying to do. This is because macros, including parameter map lookups, are evaluated first before the query engine executes queries.
The best suggestion I have for you is to create a database table to store the lookup key and name, import it as a query subject and create a join to the oocr query subject.
If there is some reason that you can't do the above and really need to manage the lookup values in FM then you could look into creating a virtual table using Cognos SQL inside a data source query subject. Another alternative, only if oocr is the only query subject that needs to lookup these values, would be to create another query item in oocr for ocrname that uses a case statement.