Stack-over detection is enabled by setting "stack" for the memory attribute in the configuration dialog box.
ID78K4 User's Manual
Configuration dialog box
Moreover, to test the size actually consumed as the stack, fill the memory capacity in the vicinity of the stack with a special value prior to program execution, and following program execution, count the bytes that have been overwritten.
Determining the number of overwritten bits on the memory display is easy when using 0x11 as the special value.