I blatantly borrowed this from tabletpcreview forums as Bing dug it up. Just wanted to give credit where credit is due. See if this works:
"Here's how to make "hibernate" show up as a shutdown option.
NOTE: These instructions assume you have a USB keyboard/mouse hooked up. We need to enter safe mode where by default, touch input is enabled. Also, if you haven't drive encryption, it seems Windows will prompt you for a Bitlocker password before you can enter safe mode. I had drive encryption disabled already so this didn't happen for me.
OK, enter safe mode (for instance, by selecting the option using msconfig). Enter the control panel and search for "power buttons"; you should get a page that lets you choose what the power buttons do. Click the button to "change settings that are currently unavailable", then scroll down and check the box to "show hibernate" in the power options. Reboot normally and the "hibernate option" will still show up in your shutdown menu."