Don't know if this'll help, but I often change the gradients in Flexi 5.7.
You must go to Define Gradient and pick one, then click the colour triangle under the bar. Then go and doubleclick the colour box, and pick a new one from the 60 or so that are shown.click apply or ok. Then go and click the other colour triangle on the gradient blend bar, then double click on the colour box, and alter it too. You can add more colours by clicking in a new position under the gradient bar.
Then ok it all, select the angle eg 90 degrees, or lineal/radial etc. Then select the object or text to be filled and click the object colour box and choose the gradient you just created.
Hope this helps.