If you can't get the normal flavors with it...you can also try orange juice. I use it for my 028. I also throw in sports drinks sometimes...unknown brand in the US but it would be something like gatorade.
What I found doesn't work well are carbonated soda drinks, not only does it end up in a super sticky mess because of the amount of sugar they put in them, but the carbon dioxide reacts too, which probably is doing more harm than good to whatever it's reacting with.
If you want to go exclusively EN for a while, I think the most important thing is DO NOT CHEAT with solid food..once you cheat, you want to cheat the next day too and the next day, since you've now tasted the forbidden fruit so to say. It's far easier to stay on it if you don't cheat, since your taste for solid food just goes away after a while.
As far as mixing the actual powder, use a proper bottle, this stuff is full of sugar (as it should be, the majority of your calories should be coming from carbs), it can easily become messy.
I use one of these bottles. They're great, since they close properly.
