I looked more into the plugin details (https://wiki.jenkins-ci.org/display/JENKINS/Shelve+Project+Plugin) and understand that the plugin works by having a zip file saved onto the Jenkins server. When needed to "unshelve" the project, the information is then restored from the zip that was previously created.

The actions of the plugin are actually transparent to RTC is treats this procedure as just a deletion removing the entries in the database. Additionally the zip cannot be used to restore database entries of the build history. One workaround that has come to my attention is to revoke the "Delete Build Result" permission. By revoking the permission it will preserve the history from being deleted.

If this workaround does meet your standards then I would suggest opening an RFE (Request-For-Enhancement) as this isn't really an issue within RTC. An RFE can be opened up here, http://www.ibm.com/developerworks/rfe/ .