Windows vista and IE8

Hi, I have a problem with my treo Pro, is not possible syncronize with an
old version outlook 2000, when I conect a Palm Treo Pro, ..." Microsot
Outlook it´s not a default email service". I Try to select a Microsoft
Outlook as a default email service, but I can´t , In microsot support said
select de program, but Microsoft Outlook 2000 is not in the programs to add
a default mail client. I have and Internet Explorer 8

Thanks