Aravits, You do need to have vectors (either text, or custom shapes, or vector masks) in your file if you want to retain them in your file. Vectors files that have been rasterized are bitmap and not vectors anymore...
The file formats that can retain vector info without being rasterized are PSD, PDF, and the "new" Tiff (the ones produced by Photoshop 7). The EPS (and DCS, the special EPS with spot colors, you don't encounter them unless you work in the print industry) containing vector being rasterized the next time they'll be opened in Photoshop.
For the people having an hard time figuring what we are talking about, hop to Page 53 and 54 of Photoshop's User Guide, there is a section titled "About bitmap images and vector graphics"
Or in Help>Photoshop Help (F1), go to the index, and in "V" you'll see "Vector Graphics > About"
To see if you've got a vector mask and not a bitmap one on a layer, the vector one has a vertical line before the chain icon.
Ik ben van het Franstaalige paart van Belgie, maar, ik ken en beetje Nederlands (het was mijn tweede taal, nu, mijn Engels is toch beter, nee? )
CA tutorial: Sorry, but by contract, I cannot give it away for a certain period. 
AFAIK, the mag should be available in Netherlands and US....
You'd have to buy the mag (issue #83) to read it... (and no, I'm NOT paid by the number of issues sold 
) I am still waiting of rhte issue they are supposed to send me. I just saw a part of it thanks to a member of Computerarts.co.uk 's forum
The technique involves simplification of the image, the use of different methods to select a given level of shade, then using the convert selection to path icon to turn it to Vectors.
There is also an action set, with different rendering styles.
