New user signup for Subscribe membership

[fionix]

I have setup a subscription for a specific forum people can pay to get access to.

Now I would like if NEW / Unregistered users visit the site and they want to pay right a way to get access to this forum, not to first register as a user and then go back to pay for a subscription.

Isn't it possible to get people subscribe directly and once they have paid they will need to register and will become the Paid member privileges at this time?

Hope someone knows what I want to do and that there is a simple solution to it.