NewTask() with subclass

I need to have my application launch a "new task" view, but the item must be subclassed (i.e. GW.MESSAGE.TASK.CCOCUSTOM etc.).

One way I have done it before is to create the item in the mailbox as a draft item in GW using the Object API, then open it for editing via the Token API.

However, I need to allow the user to cancel the item without leaving cruft in the mailbox/folder...

Is there a way to open a new item view with a subclass without creating the item in GW first?

Thanks.

--sk.