WordPress MU

So i've been attempting to get my subdomain blogs to appear as http://www.subdomain.com using WP 3.0. I've been able to get as far as http://subdomain.com using Donncha's domain mapping plugin, but i can't figure out for the life of me how to get the www working. I've tried a lot of different fixes on the forums, but none of them have seemed to work, and always seem to end in either a redirect loop on the admin page or something similar.
I don't care if my primary domain is http://primary.com, but my client is really adamant about having all the subdomain blogs displaying within the www. Has anyone been able to do this, and can give me some guidance?

my client is really adamant about having all the subdomain blogs displaying within the www.

can give me some guidance

Honest answer? Educate your client. Ask them if they want to give up 50% of their traffic since (unless you put in a 301 redirect from the without to the 'www') the without won't resolve.

If you really want to go that route, I would open up the database and manually edit where it exists without. That would be the database table that Donncha's plugin creates. (We use a different solution and I don;t have the table handy)

As an aside, your use of 'subdomain' is incorrect. I believe you mean addon domain. A subdomain is another site off of the (in this case and to use your example) primary domain or primary.tld.

Hope this helps and good luck. We're all faced clients who knew they were right. I should tell sometime about the churche who wanted the 180 meg audio file to load and play before their website loaded. This was back in about '98 when 99% of the web was still dial up.

Yeah, i've already tried going that route. He agrees that in terms of SEO there's no real benefit, and that it's totally based on preference... but the client is always right, and i can't exactly refuse him.

I called them sub domains in my example because WP is installed as http://primary.tld. The blogs i'm creating are... http://subdomain.primary.tld. I'm using Donncha's plugin to map http://subdomain.tld to this, so it appears if they're totally unrelated domains. The only problem left is adding the www to this.

So he wants http://www.subdomain.primary.tld ?

Also - WP 3.0 is still in Beta (or is still advanced Alpha), is it really wise building a customer site on unreleased platform?

I believe they're trying to do http://www.subdomain.tld.