Can't send Network Solutions email from iPad

I have a couple of domains registered with Network Solutions and I have a couple of corresponding email accounts. Both my iMac and my iPhone can send and receive email from those accounts. However when I tried to set up the accounts on my iPad2, it only receives email but will not allow me to send from either of my NS accounts. It says my email address "was rejected by the server." Everything is set up correctly as far as Apple is concerned, they suggested I talk with Network Solutions. Network Solutions says everything is set up fine on their end and suggested I talk with Apple. I have tried both of NS's suggested ports, but neither worked. I tried deleting and setting up the accounts several times. Nothing works. I finally complained enough that they escalated the problem. I may hear back in 24-48 hours. In the meantime, I'm without my business email on my iPad2. (Other non-Network Solutions accounts set up perfectly and work just fine both sending and receiving...so it's definitely something with those NS accounts.)

I was just wondering if anyone else has had this problem using the iPad2 to send email from Network Solutions-hosted email accounts and if you found a solution? The Apple Care rep said some domain hosting services will only allow you to get email on one mobile device (how archaic). Could that be the problem with Network Solutions?