If you want to fill the area between the plots, something like this (using the patch function) will work:
t = linspace(0, 12*pi, 250); % Create Data
s1 = sin(t)+2; % Create Data
s2 = sin(t + pi/6); % Create Data
figure(1)
patch([t fliplr(t)], [s1 fliplr(s2)], 'b')
grid
Without your data, this is as close as I can get.
Plotting your x-axis in 5-minute intervals could be as easy as simply re-scaling it by multiplying the x-axis vector by a constant (depending on what the current units are) to create the appropriate 'TickLabel' values.
