How pass parameters to Jenkins build

The build I'm triggering from Jenkins is not getting the parameter I am passing to it.

I'm have tried setting the build parameters for the BM Trigger Jenkins Build task to:

token=BUILDMASTER&VERSION_NUMBER=$ReleaseNumber.$BuildNumber&cause=Triggered+from+BuildMaster

and a more simple version

token=BUILDMASTER&VERSION_NUMBER=1.0.1

The BM log file would suggest that BM is trying to pass the correct thing:

1: Trigger PaxHoldRelease-Build Build in Jenkins with additional parameters token=BUILDMASTER&VERSION_NUMBER=1.0.1 and wait for completion

but Jenkins insists that it wasn't provided any parameters - although the build does at least start.

If I manually call this Jenkins url and pass in the parameters it all works perfectly:

http://jenkins/job/PaxHoldRelease-Build/buildWithParameters?token=BUILDMASTER&VERSION_NUMBER=0.1.10 the build starts with the version number passed

Any ideas?

Product: BuildMaster
Version: 4.6.2

I think I see why this is happening... it appears the extension is escaping all data in the URI (which would include the equals sign and ampersand):

We should be able to fix this and release a new version.