BSP for user's authentication

Hi,

I have two problems:

1.- How can I do a BSP which capture an User ID and check if that user exist in my Active Directory?

2.- I have just read weblog "/people/sap.user72/blog/2004/09/01/bsp-howto-fun-with-ldap-and-bsps" but I only can login using one user. If I try to connect using another users different that one, SAP shows an error message: "Could not logon to directory". I don't know why I can connect with one user only.

I hope your answers.

Thank you