Math Help - Tension with Vectors

I have currently run across a problem that I have no idea how to solve. Here is the question:

Two cranes that are directly opposite of each other are used to lift a 20000 lb cargo container from a ship. The cable of Crane I creates an angle of 30 degrees from the horizontal and the cable of Crane II creates an angle of 45 degrees from the horizontal.

Write vectors representing the tension of the cable of Crane I, Crane II, the 20000 lb cargo container, and calculate the tension on both cables.

I have no idea where to start, but I managed to draw a (rude) diagram:
http://i11.photobucket.com/albums/a1...ionproblem.jpg

Help would be greatly appreciated!

let be the tension in crane I cable ... for crane II

forces up = force down



force right = force left



solve the system for and