If it is so you should have done OEM customization here.
Refer here for high level information https://www.asug.com/discussions/servlet/JiveServlet/downloadBody/40049-102-1-58064/0513%20Make%20It%20Look%20Like%20You…
You can also get complete information here (Please noe this is for OEM partners alone)
http://help.sap.com/businessobject/product_guides/boexir4/en/xi4_oem_customization_en.pdf