Extending a Windows XP VM disk

Hi,

Little confused, as to extedn a disk for a VM i usllay edit its settings using the VI client and extend the disk to a new size..then use disk part..

But in Winxp the option is grayed out - even when the Xp VM is off..

Anyone know why this is and how i can extend the disk?

Disk is IDE - does this need to be converted to SCSI? if so how do i do this?

Thanks

Sam