We understand that having the outbound texts be sent from something like a Callrail number would be beneficial. However it isn't possible in the system, and we won't be making it a feature. The texting is integrated throughout our system and goes through several very integrated API steps to make sure it get backs to the lead that called. By having Twilio as our texting service it let's us get that required integration in InvestorFuse. If we allowed that to be overwritten with another service like Callrail it would hinder, and reduce reliability for texting within the system.
Simply adjust your SMS Signature to reflect the "call-to-action" you want your seller/buyer to take. You may include a website, a preferred phone number, or an email address for them to reach you back on. This may be adjusted in your Settings app in your Configuration workspace. Just look for the 'SMS Signature' field and adjust accordingly.
Let us know if you have any questions on this.