Using custom fields in a ROS service

edit

I'm trying to create a service to handle point clouds. Ideally I'd use a pcl::PointCloud<pcl::PointXYZI> but I'll even settle for sensor_msgs::PointCloud2.

When I try and create my service.srv as:

sensor_msgs::PointCloud2 cloud_in
---
sensor_msgs::PointCloud2 cloud_out

I get

error: <class 'genmsg.base.InvalidMsgSpec'>: sensor_msgs::PointCloud2 is not a legal message field type

EDIT:

the correct format should be sensor_msgs/PointCloud2 cloud_in