You'll have to make a new .material file for that image then.
Go to your Feralheart >> Media >> Objects folder and copy and paste a .material file from there into your maps' folder (or where ever you please).
Open it up with a program such as Notepad (right-click >> Open/Open With >> Notepad) and replace it with this:
material NAMEMat
{
technique
{
pass
{
ambient 0.1 0.1 0.1
cull_hardware none
cull_software none
texture_unit
{
texture ice.jpg
}
}
}
}
Where it says NAME just typed in whatever you want, for example I would type "icegroundMat". You shouldn't need to change the image name, it's using the ice image that you are using for your map.
Go File >> Save and you should be good to go :3