Yocto toolchain installation with qscxmlc support

Question

Hej Folks.
I try to implement a yocto and QT5 based project for a variscite board with QtSCXML support. I got everything run on QtCreator for my Hostmachine (Ubuntu 64-bit, 18.04), so I know my project has to be kinda right. For the yocto part, I used the installtion guide by variscite itself (Ref_1 and Ref_2). As targetmachine I use the VAR-SOM-6UL.

So my toolchain building process is the following:

$ sudo apt-get install gawk wget git diffstat unzip texinfo gcc-multilib \
build-essential chrpath socat cpio python python3 python3-pip python3-pexpect \
xz-utils debianutils iputils-ping libsdl1.2-dev xterm     
$ sudo apt-get install autoconf libtool libglib2.0-dev libarchive-dev python-git \
sed cvs subversion coreutils texi2html docbook-utils python-pysqlite2 \
help2man make gcc g++ desktop-file-utils libgl1-mesa-dev libglu1-mesa-dev \
mercurial automake groff curl lzop asciidoc u-boot-tools dos2unix mtd-utils pv \
libncurses5 libncurses5-dev libncursesw5-dev libelf-dev zlib1g-dev bc rename 
$ mkdir ~/bin (this step may not be needed if the bin folder already exists)
$ curl https://commondatastorage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
$ chmod a+x ~/bin/repo
$ export PATH=~/bin:$PATH
$ mkdir ~/var-fslc-yocto && cd ~/var-fslc-yocto
$ repo init -u https://github.com/varigit/variscite-bsp-platform.git -b dunfell      
$ repo sync -j$(nproc)   
$ MACHINE=imx6ul-var-dart DISTRO=fslc-x11 . setup-environment build_x11

Now I change the local.conf file in ~/var-fslc-yocto/build_x11/conf/. As default the connectivity check fails, so a diffrent url is deposited. The virtualization is only activated to suppress warning messages. To "include" the qtscxml, its append to the IMAGE as the nativesdk-qtscxml is append for the host toolchain.
But see for yourself:

MACHINE ??= 'imx6ul-var-dart'
DISTRO ?= 'fslc-x11'
PACKAGE_CLASSES ?= 'package_rpm'
EXTRA_IMAGE_FEATURES ?= "debug-tweaks"
USER_CLASSES ?= "buildstats image-mklibs image-prelink"
PATCHRESOLVE = "noop"
BB_DISKMON_DIRS ??= "\
    STOPTASKS,${TMPDIR},1G,100K \
    STOPTASKS,${DL_DIR},1G,100K \
    STOPTASKS,${SSTATE_DIR},1G,100K \
    STOPTASKS,/tmp,100M,100K \
    ABORT,${TMPDIR},100M,1K \
    ABORT,${DL_DIR},100M,1K \
    ABORT,${SSTATE_DIR},100M,1K \
    ABORT,/tmp,10M,1K"
PACKAGECONFIG_append_pn-qemu-system-native = " sdl"
CONF_VERSION = "1"

DL_DIR ?= "${BSPDIR}/downloads/"
ACCEPT_FSL_EULA = "1"

#check connectivity using google
CONNECTIVITY_CHECK_URIS = "https://www.google.com/"

#enable virtualization to disable warning
DISTRO_FEATURES_append = " virtualization"

#image extra
EXTRA_IMAGE_FEATURES = " \
    qtcreator-debug \
    ssh-server-openssh \
    debug-tweaks \
    tools-debug \
    "

#use systemd
DISTRO_FEATURES_append = " systemd"
DISTRO_FEATURES_BACKFILL_CONSIDERED_append = " sysvinit"
VIRTUAL-RUNTIME_init_manager = "systemd"
VIRTUAL-RUNTIME_initscripts = ""
IMX_DEFAULT_DISTRO_FEATURES_append = " systemd"

#image install
IMAGE_INSTALL_append = " \
    qtscxml \
    "

#toolchain host
TOOLCHAIN_HOST_TASK += "qtscxml \
    nativesdk-qtscxml \
    "

Now comes the happy building part and the Problems beginn!
I will just type what i'm doing:

$ bitbake -c populate_sdk fsl-image-qt5
$ . ~/var-fslc-yocto/build_x11/tmp/deploy/sdk/fslc-x11-glibc-x86_64-fsl-image-qt5-cortexa7t2hf-neon-imx6ul-var-dart-toolchain-3.1.sh 
$ . /opt/fslc-x11/3.1/environment-setup-cortexa7t2hf-neon-fslc-linux-gnueabi
$ cd ~/TestProject
$ mkdir build
$ qmake -makefile -o build/MakeFile test.pro
$ make -C build/

And now the error message i receive ..

make: Entering directory '/home/yocto/TestProject/build'
make: *** No rule to make target '/opt/fslc-x11/3.1/sysroots/x86_64-fslcsdk-linux/usr/bin/qscxmlc', needed by 'custom_statemachine.h'.  Stop.
make: Leaving directory '/home/yocto/TestProject/build'

(custom_statemachine.h isn't written by me, I only generated custom_statemachine.scxml)

Do i missed something? Why is Qts SCXML Compiler qscxmlc missing?
Thanks to everyone how read this far, thanks for every suggestions and sorry for every grammatical mistake.