www.<<domain>> for domain aliases not created automatically in IIS

[AngusG]

I have a root domain domain1.com. Creating this has created host header values entries in IIS for domain1.com and www.domain1.com

Creating domain alias domain2.com creates the host header value domain2.com in IIS. I have to create www.domain2.com manually. At some random point this www.domain2.com entry disappears and it then resolves to the Plesk default page. My guess is that Plesk publishes all its info to IIS and my manual entries disappear.

How do I set up these www.<<domain>> entries for domain aliases in Plesk so they are published to IIS by Plesk and I don't have to create manual entries.

EDIT: forgot to add: Windows 2003 64bit + Plesk 9.2.3

Thanks,
Angus.