Have you read the Hardware Interfaces Document? WICED Smart Hardware Interfaces
Access to the low level I/O registers is usually not possible, as BCM has created an abstraction layer on top of them and provided the APIs to ask the hardware to do the work.
frro_352456 has done an excellent job explaining how to configure GPIO on our part within the datasheet for their Embedded Masters Break-Out Board: http://www.cdiweb.com/datasheets/embedded/EMRF-BCM20736S-BOB-UserManual.pdf
Start on page 49.
In addition, the new Smart Designer feature in SDK 2.X can also be used to setup GPIO.
When using this tool, pay particular attention to the "To-Do' list as these are sections of code that still need to be manually programmed. Smart Designer does the rest.