If you live anywhere in the EU, the company has to charge you VAT. If you try to cheat the system, firstly you are attempting to commit fraud, which is a criminal offence, and secondly you're just messing MobiPocket around, and the odds are that your order will simply be cancelled.
"Don't do it" would be my advice.
You could perhaps look at buying from, say,
Fictionwise who are outside the EU and hence won't charge you VAT.