Help request NSIS/Java/Azureus

I have just started learning NSIS yesterday .
What I want to do is make a launcher for Azureus to
replace the original "Azureus.exe" because it is made with a
non-open source tool (exe4j) .
I can launch Azureus with the launcher I made as long as
I don't try to pass any command line options to it but I want the launcher
to define where the settings and default install-dir are located .
here's what the script looks like so far :

-----------------------------------------------------------------------
Name "Azureus"
Caption "Azureus"
Icon "Azureus.ico"
OutFile "Azureus.exe"
SilentInstall silent
AutoCloseWindow true
ShowInstDetails nevershow
!define APP "Azureus"
!define VER "1.0.0.0"
!define CLASSPATH "swt.jar;Azureus2.jar"
!define CLASS "org.gudy.azureus2.ui.swt.Main"

Section ""
Call GetJRE
Pop $R0
StrCpy $0 '"$R0" -classpath "${CLASSPATH}'

SetOutPath $EXEDIR
Exec $0
SectionEnd

Function GetJRE
Push $R0
Push $R1

ClearErrors
StrCpy $R0 "$EXEDIR\jre1.6.0_02\bin\javaw.exe"
IfFileExists $R0 JreFound
StrCpy $R0 ""

ClearErrors
ReadEnvStr $R0 "JAVA_HOME"
StrCpy $R0 "$R0\bin\javaw.exe"
IfErrors 0 JreFound

ClearErrors
StrCpy $R0 "$R0\bin\javaw.exe"

IfErrors 0 JreFound
StrCpy $R0 "javaw.exe"

JreFound:
Pop $R1
Exch $R0
FunctionEnd
--------------------------------------------------------------------------
Here are the commands I want to use :
-Dazureus.config.path=$EXEDIR\settings
-Dazureus.install.path=$EXEDIR
-Duser.dir=$EXEDIR

No matter what I do I get an error telling me that
"Exec expects 1 parameters, got 5."
and that leads me to believe it's a syntax-error
( I write the script in notepad++ )

I can start azureus form a DOS-prompt with something like this :
(full path to the jre)javaw "-cp swt.jar;Azureus2.jar" "-J-Xmx64m" "-J-Xms12m" "-J-XX:NewSize=6m" "-J-XX:MaxNewSize=10" "-J-XX:SurvivorRatio=6" "-J-XX:+UseParallelGC" "-J-XX:GCTimeRatio=9" "-J-XX:AdaptiveSizeDecrementScaleFactor=1"
"-Dazureus.config.path=Azureus_Portable\settings" "-Dazureus.install.path=Azureus_Portable" "-Duser.dir=Azureus_Portable" "-Dazureus.nativelauncher=1" org.gudy.azureus2.ui.swt.Main..

So, how do I do that with NSIS ?
I did search (and read the man) but I still don't get what I'm doing wrong ?
Once I have the launcher working I plan on making a Azureus Portable launcher so it works with the portableapps directory-structure .

Any suggestions will be appreciated