Getting pressure when entropy and temperature is given (Rankine cycle - superheated vapour)

I am using Xsteam.m file for linking steam table in MATLAB, but i'm stucked when i had to calculate pressure and i was given corresponding temperature of superheated steam and the entropy of the same! For example say i am given that at temperature of 500C, entropy of superheated vapour is 8.41. What would be the corresponding pressure?? Using steam table, i can find the answer as 2.5 bar easily! But how can i do it in MATLAB?? Reply asap!

[Walter Roberson]

My "asap" reply is that I don't know. Did that help?