Does anyone know if its possible to send email from a Clear email address using Slingshot as your internet supplier.

My mother in law uses a Clear one currently on Spark/Xtra which has been OK until recently - after many issues a while back when you had to get an xtra email address and register the Clear email address. Its stopped working again and i'm taking the opportunity to look for a better deal for phone/internet which Slingshot appears to be ( $75 odd vs $95 for Voda or Spark )