subdomain DNS(?) issue

[sketchy]

I'm in Australia, so I'll clarify a couple of things here. Telstra, optus, vodaphone are all cell phone service providers. Telstra is also an ISP.

OK, so here's the thing. I have a site for which I have set up a wap subdomain, let's call it wap.mysite.com. In the wap directory for the site (which the subdomain points to) is a php file, which determines what is calling the page, and serves the appropriate wml, or html, page.

From dial up/broadband though a number of providers (including telstra), this works fine. From wap through optus/vodaphone it works fine. From wap through telstra, the subdomain is totally disregarded, it serves www.mysite.com.

The subdomain was set up several days ago, and was initially set up to point to the wap directory, so I don't believe it's a DNS refresh issue. The only thing I can think of is that telstra has a whack wap gateway. I have spoken to telstra technical people, and they have no idea what's going on. I'm hoping that someone here may have some clue as to what is causing this...