I have a NTM 2008 S17 hybrid and am wondering about mattress storage while bunk ends are closed. The rear bunk has space to secure the mattress in an upright position but not the front bunk that I can see. The former owner told me he just put the front mattress on the u-shaped dinette while traveling. I don't see any indication of any ties to support it in an upright position like many hybrids have. I'd like to be able to put it somewhere to be able to use the dinette berth if I'm not extending the bunk ends. Anyone with wisdom to share ??