QUOTE(rosfrog @ May 26 2009, 05:54 PM)

If you can't do it, it could come from several things :
1) you're keeping too much weight in the voice too high - this is often the case when we've been taught that 'chest' and 'head' and 'mix' are 'different voices'.
2) you're not anchoring properly in the back of the neck, the obliques and the back.
3) you're not tilting the larynx as you go up
4) you're constricting the false vocal folds as you rise
5) you're simply trying to use the wrong mechanism to do something it's not designed to do.
If 1) the answer is to learn to thin out the sound as you rise by dropping weight. NG sirens are a good way to learn this. Start very softly and build volume gradually. Alternatively, send all the vowels towards a little dumb 'uh' sound (like the emphatic 'duh' !)
If 2) learn how to anchor the back, neck and obliques (there are other muscles involved, but anchoring the obliques will usually make them come into play) - using lots of voiced fricatives such as 'v' or 'z' on one octave sirens will help with this, but it's best for a teacher to show you.
If 3) Whimper gently as you ascend the scale to encourage tilting and apply the vowel trick from 1.
If 4) sob into the sound as you go up, or imagine that you're going to laugh and can't be seen to laugh, so have to hide it in your throat.
If 5) Try crying hard into the sound as you go up - think major stomach ache, or the end of some terrible hollywood movie where the star kneels on a dirty rooftop in the rain and cries 'nooooooooo' to the heavens (we've all seen THAT film!) - keep that cry working hard in the voice as you go up.
The problem you'll have is that you won't find it easy to identify your problem yourself and an expert ear can be very helpful in these cases. Do you have a teacher? If so, what does (s)he say about it? What strategies have they given you for fixing it?
If you don't have a teacher or feel that you aren't getting the answers you want from your teacher, I'll happily give you a 30 minute slot for free on Skype to work on it together and analyse your problem so you can get some concrete strategies for fixing it.
Good luck!
Allan
Hello Rosfrog, thank you very much for the welcome and the helpful tips.
In fact I do have a vocal teacher (once a week, every friday at school) and quite surprisingly while working on this song, she suggested point 3 and 4 (the cry, the whimper and possibly the sob) at the end of my last sessions to help with my problem.
I will print out your suggestions and show them to her the next time i see her (which will be the 5th June as this week, its a school holiday and i'm sure she will assist me with these problems and in the meantime, I would be very grateful if you could guide me further through the points you have suggested in some form (by maybe reffering me to some videos which already may cover the problem as point 1 and 2 is very new to me.) and i think i should take advantage of the practice time from now to the next time i see my teacher as my performance date is drawing near.
I do have skype, my screen name is: mda.mak
Thank you very much for the helpful tips.