Qt + KDE widget doubt in Debian Sarge

[hildebrand_us <hildebrand_us@yahoo.com>]

I have got Sarge installed on my system. I have the following doubts:-
(1) I want to use kde widgets within qt3 designer. In particular i wanted to use the KDoubleSpinBox widget. I am not finding the relevant header file in /usr/include/kde which also i had to manually specify in the make file. Where are they? Do i need some other package to be installed to get the header file. Other kde widgets seem to be there. (some are missing like kintspinbox). My code refuses to compile here due to this. Any suggestions anybody? The widget works fine in preview though!! I don't see this class also in the kde core class list available inside in /usr/share/doc/kde. Where did this come from.  

(2) I want to add my qwt widgets also to the designer toolbox. how can I do that? Shouldn't the plugin be installed when i had installed libqwt4-dev package? I don't see any plugin package there. 

(3) Where is the help available for the kde widgets? (qt widget help is ofcourse got through qt3-doc). It would be really useful.

I had installed kdesdk, libqt-mt-dev and qt3-designer among other packages. kde-devel etc ofcourse got installed directly. 
If anybody can guide I would appreciate it.