Updates listed git svn submodules. I am sure there is a more generic way to accomplish this, but it works for my needs.

update_submodules.sh

#!/bin/sh

ROOT=/Volumes/git

#SM_ROOT=zero
#SM_SUBMODULES=( CORE/dojo )

AB_ROOT=appbuilder
AB_SUBMODULES=( BUILD/zero.build BUILD/zero.docs BUILD/zero.findbugs.ext BUILD/zero.infocenter.build BUILD/zero.infocenter.feature BUILD/zero.infocenter.updatesite )
SUBMODULES=(${AB_SUBMODULES[@]}) # ${SM_SUBMODULES[@]}

ORIGIN_PWD="${PWD}"

cd $ROOT

ELEMENTS=${#SUBMODULES[@]}
for (( i=0;i<$ELEMENTS;i++)); do
    directory="${ROOT}/${AB_ROOT}/${SUBMODULES[${i}]}"
    if [ -d $directory ]; then
    	echo "Updating ${directory} ..."
    	cd $directory && git svn rebase && cd $ORIGIN_PWD
    else 
    	echo "${directory} does not exists"
    fi
done

cd $ORIGIN_PWD