Kwato,
You will be able to use the 2700 to control your big dish. You will need a Vbox II to control dish movement, the 2700 already has the connections for controlling the polarotor. Your setup sounds a lot like what i have, i have a feeling you are really going to like what you are able to view, and the ease of use after you set it all up. The Pansat 2700 is perfect for this application because it will do diseqc commands to the vbox II, and also control polarotor, eliminating the need for an analog box to control the dish. Also it has a nifty little universal remote, very useful :-D
You will find that you have to fine tune stuff for the ku side, what seems perfect for C band can be way off for KU band. Of course once you have all the sats dialed in for ku band, the c band is usually perfect :-D
The way to set up the system (once you have the vbox II) goes like this:
Using your existing run of 5 leg c band ribbon cable use the RG6 from both your ku lnb and c band lnbs and connect them to the DiSEqC switch. Just to keep this easy, run your c band to port one, and your ku to port 2. From the diseqc switch run 1 line of rg6 to the vbox II. From the VBox II run 1 line of RG6 to the LNB input on the back of the Pansat 2700. Connect the three wires running to your polarotor of your big dish (pulse, ground, +5) to the back of the Pansat. You are now ready to start playing with your system.
Good luck, if you have more questions please feel free to ask.