When you invoke the step function you are multiplying your function on the frequency domain by 1/s, the function you get from that operation is then converted to the time domain using the ilaplace function.
Now for you specific case you can first convert the function to the time domain using ilaplace and then multiply by sin(t).
For the plot make the t vector and use the plot function to plot the response
plot(t,f(t))
Example
syms s t
TFC=evalc('tf([1 1],[1 1 1 0])')
%subplot(211)
[a b] = strread(TFC, '%s %s', 'delimiter',char(10));
num=sym(char(a(2)));
den=sym(char(a(3)));
tft=ilaplace(num/den);
tt=0:0.01:10;
plot(tt,subs(tft,t,tt).*sin(tt))
title('f*sin(t)') %response to input sin(t)
ylabel('Amplitude')
xlabel('time')
