My suggestion is rather than trying to change WTF sparring into ITF sparring, why not just go join the ITF so you can compete at their tournaments?
Oh, I'm just making conversation, for the most part.
With that said, I probably WOULD be ITF if there were good ITF schools around me, but there just aren't. I was involved with them for a bit (or the USTF, technically), but I had problems both with my instructor and some of the things going on in the organization. I actually did e-mail a local ITF instructor who I might want to train with just last night, but his class is really way too far for me to get to since I don't have a car.
My reasons for switching over are basically thus:
1. Quality of instruction - I really like the guy at my new WTF dojang and he has produced some good competitors, including one guy who tried out for the national team last year.
2. Lots of Sparring - There's not much of a sparring emphasis in the local ITF/USTF classes. I was with my instructor for 4 months and never once did ANYONE spar, regardless of belt color. At my new WTF school there are two sparring days a week and, unlike at a lot of TKD schools, he throws you into it immediately instead of making you wait 3 months or 6 months or whatever.
3. Distance from My Home - Easy to get to via public transportation.
4. Great Kicks - I really do enjoy kicking and WTF guys often have beautiful looking kicks.
5. Already Taking Karate - I would be more upset about the lack of hands in WTF TKD if it was all I'm doing, but I get plenty of hand training in my wado-ryu class, so I'm really not that worried about it.
6. It's Different - WTF TKD is different from everything I've done in the past. I think it's interesting. As long as I look at it purely as a sport, then I'm okay with the ruleset.