Revision history [back]

After trying a bunch or permutations, this is what it worked for Vector3Stamp

2176decaecbce78abc3b96ef049fabed header
4a842b65f413084dc2b10fb484ea7f17 vector

So they're not concatenated as the documentation says. What happens is the MD5 hash of the underlaying message replaces the type itself. so std_msgs/Header becomes 2176decaecbce78abc3b96ef049fabed and geometry_msgs/Vector3 becomes 4a842b65f413084dc2b10fb484ea7f17

I would recomend updating the docs to reflect this behavior.