I'm not a mapleflow user but page 28 section 5.4 of the user manual gives a way to enter them

is this the one your looking for:

https://www.mapleprimes.com/questions/39128-Modify-Help-Pages

@Kitonum If the first int command is proceeded with the :- operator maple should use the kernel int command instead of the Vector Calculus version. Remember Carl posting something about this a few months ago.   

to obtain the transfer function isolate the system of equations for Vo by using solve, eliminate, ect then divide the whole thing by Vs. I don't have maple handy to supply an example