You could always delete Email ISP addresses with the old version it was just a matter of clicking on it and clicking remove.
I don't have Incredimail any more as Emisoft kept flagging it as a trojan downloader.
When I had XP you could right click the taskbar and select properties.Start menu customize.And in the dropdown bar you just added Incredimail as you main e-mail provider.
Now like I said it has been a while so may not be correct it but it is in the same area if you look.
Has he already got it set as the default e-mail provider.