Is it possible to use 2d Lidar for Occupancy Map Building while using Stereo Odometry in RTAB-Map?

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Hello,

I have a differential-drive robot that is equipped with a Realsense D435 RGBD camera and 2D Lidar scanner. I am using RTAB-Map to perform SLAM and I wanted to know if there is a way to incorporate Lidar readings from the /scan topic into the RTAB-Map SLAM node rtabmap. I have chosen to use the stereo mode of the camera to receive stereo images that will be input to the stereo_odometry and rtabmap nodes. When I run the launch files that I use, the map cloud and odometry work fine along with the /scan topic producing messages. However, when I try to view the produced occupancy grid from the Lidar, I get the follow error message continously:

[ WARN] [1679412963.381777182]: Grid map is empty! (local maps=1)

Through further investigation, I realized that the rtabmap SLAM node is not subscribed to the scan topic even though I set subscribe_scan=true. The launch file that receives stereo images and launches the standard rtabmap launch file rtabmap.launch will be placed below:

<launch>

<arg name="rviz" default="true" />

<include file="$(find rtabmap_ros)/launch/rtabmap.launch">
    <arg name="rtabmap_args" value="--delete_db_on_start"/>
    <arg name="frame_id" value="base_link"/>
    <arg name="stereo"         value="true"/>
    <arg name="subscribe_rgbd" value="false"/>
    <arg name="subscribe_scan" value="true"/>

    <!-- stereo related topics -->
    <arg name="left_image_topic"        default="/camera/infra1/image_rect_raw" />
    <arg name="right_image_topic"       default="/camera/infra2/image_rect_raw" />      <!-- using grayscale image for efficiency -->
    <arg name="left_camera_info_topic"  default="/camera/infra1/camera_info" />
    <arg name="right_camera_info_topic" default="/camera/infra2/camera_info" />

    <arg name="rgbd_topic"  value="/rgbd_image"/>

    <arg name="compressed"  value="true"/>
    <arg name="rviz"        value="$(arg rviz)"/>
    <arg if="$(arg rviz)" name="rtabmapviz"  value="false"/>  

</include>

<!--Launch static transform between base_link and camera_link-->
<node name="base_to_camera_static_publisher" pkg="tf2_ros" type="static_transform_publisher" args="0.2531 0 0.0859 0 0 0 base_link camera_link"/></launch>

Please note that this launch file is being used on a remote computer and the robot is using a separate launch file that initializes the stereo_sync node along with the driver for the 2d Lidar. This launch file will also be displayed below:

<launch>

<!-- Launch Stereo Camera Node-->
<include file="$(find realsense2_camera)/launch/rs_camera.launch">
    <arg name="enable_infra1" value="true" />
    <arg name="enable_infra2" value="true" />
</include>

<!-- Launch LD14 Lidar Sensor Node-->
<include file="$(find ldlidar_sl_ros)/launch/ld14.launch"/>

<!-- Launch RTAB-Map Stereo Sync Nodelet-->
<arg name="rate"  default="5"/>
<arg name="approx_sync" default="false" /> 
<arg name="stereo_sync" default="true"/>

<node pkg="nodelet" type="nodelet" name="nodelet_manager" args="manager"/>
<node if="$(arg stereo_sync)" pkg="nodelet" type="nodelet" name="stereo_sync" args="load rtabmap_ros/stereo_sync nodelet_manager" output="screen">
    <param name="compressed_rate"  type="double" value="$(arg rate)"/>
    <param name="approx_sync"      type="bool"   value="$(arg approx_sync)"/>

    <remap from="left/image_rect"        to="/camera/infra1/image_rect_raw"/>
    <remap from="right/image_rect"       to="/camera/infra2/image_rect_raw"/>
    <remap from="left/camera_info"       to="/camera/infra1/camera_info"/> ...