supporting complex data types

Hi
If we use some complex datatype (as parameter/return value) in one of the functions of a Web Service, then the Web Service client would need the following apart from WSDL file:
1) binaries for complex datatype
2) binaries for serializer and deserializer for the complex data type
Where would Web Service clients get this from? 
Do these reside at the same place as WSDL? 
Does UDDI have any information about the location of these?
thanks,
regards,
Naresh Agarwal