vill ha -> want (to have) ?
I think 'want to have' (not just 'want') should be allowed as a translation of 'vill ha' in most of the cases. Sure, maybe 'want' is the more appropriate translation BUT I'm pretty sure you can use both. Or take it the other way around: How would you translate "I want to have sth."? 'Jag vill ha någonting' is the most appropriate translation imo.
I am sure you mean "Jag vill HA någonting" :) and yes that is how I would translate "I want to have something" as well (or maybe the short "något" instead of "någonting").
Do you mean that for example "Jag vill ha en hund" can only be translated to "I want a dog" and not to "I want to have a dog", and that you want both to be accepted?