Q: how to send a direct voicemail to an IPHONE from a Galaxy S III on Verizon wireless?

I can not send a direct voicemail using Promt 2 to send a message from my Galaxy SIII to an Iphone 5 or 4. Is there something I can do with my phone or should the iphone recepient do something with their phone so that direct voicemail can be achieved?

Both phones are on Verizon wireless. I tried to research this online. There is no information available at all! I called Verzon Wireless support, they did not know why. CAN ANY ONE HELP ME figure this out?

Thanks in advance for any help.

Alex