Hi,
I did a thread about my helios and how I learnt to modify it on the cheap. Helios... race bike type or TT?
I didn't like the telescopic handle bar stem/post either so I fitted the one you find on Speed TT and Mu SL (and many others). This type is shorter and has a T fitting that required something like the litepro stuff above.

However, while I generally like the litepro bite, do NOT use this "extender". The clamp are made of smooth soft anodized aluminium and when you get on rough road or get out of the saddle a put some weight on the front while climbing a hill, the extender stem collapses... The genuine product, Syntace VRO adaptor, fitted by Dahon and Tern is properly designed with a knurled inner surface and hi tensile bolts; these 2 things allow adequate clamping a since fitted, I've never had any other issue (even off road).