Hiding a Tab Dynamically in FPM

Hi,

Can you please let me know how to hide the tab dynamically in FPM. I tried to implement the interface IF_FPM_TABBED_CONF_EXIT in the SAP standard webdynpro, but I get a error " Web Dynpro comp./intf. "IF_FPM_TABBED_CONF_EXIT already exists". Even though I get this message I am not able to find the interface IF_FPM_TABBED_CONF_EXIT in the implemented list of interface.

Regards,

Arun