Hi Ana,
WLC Discovery process. Have a look in this good doc;
Lightweight AP (LAP) Registration to a Wireless LAN Controller (WLC)
http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a00806c9e51.shtml#topic2
For the Static entry question;
If this AP was ever registered you can use this command from the LAP CLI to clear the LWAPP configuration on the LAP:
clear lwapp private-config
This allows you to use the AP LWAPP static configuration commands again.
Here is an example:
Enable (enter password)
AP1240#clear lwapp private-config
AP1240#lwapp ap hostname AP1240
AP1240#lwapp ap ip address 10.77.244.199 255.255.255.224
AP1240#lwapp ap ip default-gateway 10.77.244.220
AP1240#lwapp ap controller ip address 172.16.1.50
Note: You cannot use the clear lwapp private-config command when the LAP is registered with the controller.
http://www.cisco.com/en/US/products/hw/wireless/ps430/products_tech_note09186a00808e2d27.shtml#t2
Hope this helps!
Rob