I Think there is a bug in the svn plugin possibly other VCS plugins as well.
When you execute teamcity via wget as documented in
for example :
Build definition bt4 queues with the System parameter TAG_NUMBER set to 188.8.131.52
If you create a command runner step with echo %system.TAG_NUMBER% the result will yield 184.108.40.206
However in the svn VCS plugin if you add a check out rule +:%system.TAG_NUMBER%=>.
which says only checkout %system.TAG_NUMBER% and send it to the root of the BuildAgent working directory
it will not work.
Furthermore if you preinitialize system.TAG_NUMBER to say 220.127.116.11 the svn VCS plugin will
pull from the 18.104.22.168 subdirectory yet the rest of the build will have 22.214.171.124 as the value
Any work arounds would be appreciated.