(As of Feb 2010) I had no idea the video I had uploaded for my personal blog became so popular! Sorry for not realizing and replying earlier. The person making the cream rose was actually my senior during my work attachment to Duc Phat Vina Bread (now called ABC) in HCM, Vietnam. A must visit if you're heading there.
Anyway, some pointers on the cream rose:
1. It's 100% whipped cream, for both colours
2. The pink portion is NOT painted on the bag! It's really about stuffing the correct amount of pink whipped cream at the side. The colour tends to get uneven when the bag is about to empty, so try to refill earlier.
3. Make your roses in a really cold room, especially if you have warm palms. After all, you're going to store the cake/rose in the fridge right??
4. I have no idea of the recipe of the whipped cream - it's actually their trade secret. Vietnamese whipped cream in fact.
5. It's not that difficult if you see what other whacky stuff they make. I learnt to make that rose myself after about 3 week's training from an absolute noob. It's all about practice and some care for your flowers :D
6. Metal tips way better than plastic ones.
7. The petals have to be squeezed out quickly and steadily - something like playing the violin. You will have drooping petals if you squeezed them out too slowly
8. Try to form the petals in an up-and-over manner inside of just simply pulling the cream to the side after squeezing. The angle which you position the piping to the rose is very important as well! Hold the piping more horizontally for the inner petals and more vertically for the outer petals.
That's the most I can explain, the rest is up to you to practice!