I'm having a problem here.

I have a small list using aweber using their follow up email (or automated emails) and I need to test subject lines. But they only offer split testing for broadcasts...

Now I need to know if there is any email provider that support split testing for automated emails?

I'm testing getresponse, but only their "newsletter" have split testing.

I offer a free ebook that must be sent instantly via email and later I have a 15 automated emails that aweber sends.

But I need to test subject lines using this automated email series...

Is there any email provider with this function? Or how can I test subject emails with automated emails on aweber?