send emal from alternate address

[gtmiller1001]

So i set up a dummy Yahoo mail acct that my corporate email is forwarded to. I changed the settings on yahoo to display my corporate email address as when sending mail (so when i log into yahoo mail and compose an email to John Doe, when he opens it it says it came from my corporate email address). I then added that dummy yahoo mail acct to my iphone. However, when i send mail from it on my iphone, it does not display my corporate email address to the reciepeint, it displays the actual yahoo address. how can i make the iphone send the mail the same way i send it when actually logged into yahoo on the computer? i want reciepeints to see the mail they reieve as if it came from my corporate email address. Help is GREATLY appreciated!