You dont need to use IOS maps on IOS Reservations as IOSR has its own map system.
Just set the hotel location's coordinations.
Go to
google maps, find the location you are interested in.
Click on the
link icon to get the URL google gives you to that exact location, this URL will be something like this:
http://maps.google.com/?ll=38.561053,22.961426&spn=3.255715,4.938354&t=h&z=8&vpsrc=6
From the above URL you need only the
ll pair (
38.561053,22.961426).
Copy-paste this into the hotel's edit page in IOSR in the corresponding field and you are ready.