I am creating an application that has multipile browsers open. Each browser has its own keyboard to type with but I don't know how to show the keyboard in this application. When the user wants to type any URL, I have to show keyword for each user.
The normal keyboard should - at least in the surface mode - appear as soon as a textbox gets a focus. The drawback: there is only on open at a time.
If you really need to have multiple touch-keyboards, you would need to implement a custom control displaying and emulating a keyboard (you would need to handle different layouts on your own!). Basically it could be implemented as a bunch of buttons, each one adding a letter to a label. A delete button would delete the last letter. Marking, copying, deleting and so one would be interesting parts to be implementing.
We have done something similar (although only one keyboard) to emulate a handy keyboard for a promotion. To be honest: it wasn't the best experience in terms of usability (a bit worse than the included keyboard). It has fit it's need, and on screen keyboards aren't best in class experience at all (you could argue, but I like my mechanical keyboard a lot more than any virtual keyboard, so this might be a matter of taste)