Call service in Micro-ROS while using custom QOS settings

- Hardware description: Portenta H7 & Ubuntu 22.04 PC
- Version or commit hash: humble with custom ros2 packages

While using custom QOS Settings as described in [https://micro.ros.org/docs/tutorials/advanced/create_dds_entities_by_ref/](https://micro.ros.org/docs/tutorials/advanced/create_dds_entities_by_ref/), creating a client for a service using Micro-ROS fails with an error:
`[XMLPARSER Error] Error parsing XML buffer -> Function loadXML`

The MicroRos Arduino library has been re-compiled to include custom ROS2 message and service types, and also configured to use custom QOS via references, as explained in the previous link.

The same code can run without that service client, while using different topics and message types, as they have been correctly defined in the "custom_qos.refs". The problem comes in when trying to add a service, as I haven't found a way to set up the QOS for a service and its request/response.

If the MicroRos Arduino library is compiled without the QOS reference setting, the client also works as expected.

So far, I tried to include the service as if it were a topic but using "rs" instead of "rt", according to the ROS Specific Namespace Prefixes standard [here](https://design.ros2.org/articles/topic_and_service_names.html#mapping-of-ros-2-topic-and-service-names-to-dds-concepts). I also tried to replicate the configuration laid out in [this ROS2 tutorial](https://docs.ros.org/en/humble/Tutorials/Advanced/FastDDS-Configuration.html#create-the-xml-profiles-for-the-service-and-client), but using a similar approach for the "custom_qos.refs" file did not work.

What's the way moving forward? Is there a way to use both custom QOS settings and ROS2 services in Micro-ROS? Or should I choose only the custom QOS or the services?

Thanks!

Reproduziere den Service-Client-Fehler auf dem Setup mit Portenta H7 und Ubuntu 22.04 bei aktivierten benutzerdefinierten QoS-Referenzen. Beginne mit custom_qos.refs und den verknüpften Micro-ROS DDS-entities- und ROS 2 Fast DDS configuration-Tutorials und vergleiche die Namen der Service-Anfragen/-Antworten mit den funktionierenden Topic-Einträgen. Als abgeschlossen gilt, wenn eine funktionierende Konfiguration dokumentiert oder die Inkompatibilität zwischen benutzerdefinierten QoS-Referenzen und Services bestätigt wurde.

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