Problem enahnicng the Lead object

Hi All

i have a very serious problem with enhancing my object

there is a stnadard object of

LEAD BUS2000108

which i am enhancing to create a new method for the LEAD object

problem is that when i am trying to release the sub object the error is coming

" Existence Check method is not redifined"

the above mentioned method is actually inherited from the standard object so why should i redifine it

and if i am redifing it and then again when i try to release it error is comin that

" to relese it you need to set the status of super object as release first"

that means i have to set the status of standard business object of lead as release which requires the access key

what i really feels is that there is something wrong

because when we try to release the sub object after enhancing it this erros should not be coming because the method that is not redifined is actually the standard method and is inherited from the original object ,so why should i refine it

please tell me what should i do

this is very crucial project requirement

any help will be highly appreciated

looking for an earliest response

best regards

ashish