No hyphen on number pad for web form

A friend of mine just discovered that he couldn't place an online order because the form required hyphens in the phone number, and Safari on the iPhone gave him a number pad instead of a keyboard.

Beyond the silliness of the web site requiring data in that format, it's rather limiting that only numbers and +, #, and * can be entered in certain fields. I'm not even sure what is making Safari decide to show a number pad instead of the keyboard, unless the form field is named "phone" or something.

Here's the page in question:
https://www.catgenie.com/store/client/account/login/
Enter a phone number (near the bottom) with hyphens and click "Register," and it doesn't complain. Otherwise it errors "Not a valid phone number (separate parts with hyphens, do not use parenthesis)." Note that you don't have to fill out the whole form to test this; it tests every field every time.

Unfortunately, there's no hyphen available on the iPhone number pad you're given in those phone number fields, so there's no way to fill out this form.

The only thing I've been able to find in a good bit of web searching is this mention of the same issue:

http://getsatisfaction.com/apple/topics/sometimeswhen_entering_in_data_in_safari_on_the_iphone_i_need_to_put_hyphens_in_with_my_p honenumbers

Does anyone know a workaround?

Thanks
D