Problems Intergrating Bot Framework with SMS

Question

I have been working on azure chat bot using the bot framework SDK v4 and I have ran into an issue. My bot needs to initiate a conversation first. I have seen some examples with proactive bot but that requires us to save the user credentials as a cookie. What I need is a chat bot that sends the first message to user via SMS to initiate the conversation. The bots needs to be able to set the recipient phone number dynamically. I have looked at integrating the Twillio channel to my bot, but the problem is that the user has to initiate the conversation to the Twillio phone number which then forwards the text to Azure chat bot. I was wondering if there is anything out there which will allow the chat bot to initiate the conversation first via SMS and the phone number of the recipient should be set dynamically. Is there anything out there currently on Microsoft stack? Our company has been a long partner with Microsoft so I would like to have the chat bot using the Microsoft Azure Bot Service. Can you please guide me or forward some documentation? Any help would be appreciated.