We have run into this issue before and unless they added something with 10 (and I can't find any reference to it). The VAR I work for is also an independent copier dealer so we work with 4-5 different vendors and we only saw the first devices with this support in the last 12 months. Of course, the worst thing about this issue is that even Microsoft's own products don't work with TLS!!! If you have an on-site Microsoft Sharepoint installation the following instructions are Microsoft's own solution!!!

https://technet.microsoft.com/en-us/library/dn592151(v=exchg.150).aspx

What you need to do is use the IIS built in smtp server as a relay. Make sure you lock down the allowed devices by IP Address though in the relay setup! You can simply add your workflow server's IP address in the allowed list. When you setup workflow, you just point back to this local IP Address and don't even put any username/password in, it will always be sent using the email address setup inside the relay. However I do believe the outgoing sender has to be the same as what your relay is using (obviously you can use whatever subject line you want). As a bonus, if you have any printers or faxes in the office that need to send out you can use this same relay for them by specifying their IP Addresses.