FM or code to change the BUPA contact person validity date

Hi All,

I am assigning "has conact person" relationship to the the organization.Now my problem is

1. Even at the first time when I am assigning this relationship, period field are grayed out so I can not assign any period and by default system is picking 01/01/... to 09/09/9999. How can I change it?

In my scenario my customer is doing future planing for example : I want a particular person should behave as a contact person for my organisation BP upto a certain date (lets say 06/31/2008) for which I am doing setting today (i.e. 06/06/2008). Do you know is there any FM which can update my validuntil ?

I tried using BAPI_BUPR_RELATIONSHIP_CHANGE but this FM is not changing the ValidUntil field (I think this is because date_to field in but050 table is the part of key). Can anybody suggest some other FM or the way in which the above FM can fulfill my requirement? Really I will appreciate if you can provide some code (I know this is too much but plzzzz).

waiting for the answer ASAP.

Regards,

Sandeep