This how to document covers Data Services 4.0 SP1
The Lookup_ext(), or Lookup Extended function allows for complex joins, return multiple values, and a flexible return policy (multiple returns).
Double click on the Query Transform and delete the default mapping for country.
Click the Functions button and select Lookup Functions > lookup_ext
Enter as shown above. The lookup table is ALPHA.COUNTRY (which has country name). The lookup is based on country ID.
The output is country name.
Execute the job
View the data in the target table and notice that Country Name is now populated