Unfortunately that is not going to be possible.
These are 2 very separate systems.
The soundbar you have has a built in subwoofer, and no provisions for connecting an external sub, whether wired or wireless.
The subwoofer you have is intended for use with a different soundbar model. It is not possible to pair these 2 disparate systems together.
If you wanted to use the sub, you'd need the original SCHTB370 soundbar, but that comes only bundled with the sub usually, though you might come across a used model on ebay occasionally with the sub missing/damaged.
My apologies for the news.
If you have any other questions, just let me know. Otherwise, please take a moment to rate my service as this is the only way I am credited for my time. Hopefully I have earned 5 Stars but if not please let me know what I can do to ensure you are satisfied. I also invite you to contact me directly with any future support needs at http://bit.ly/1QwLxGh and ask for Nathan.
Thank you, ***** ***** a nice day,