Incorrect replacement of build parameters in checkout rule for vcs

Teamcity Version: 8.0.6
VCS: Subversion

I have two build parameters

checkout_buildnumber - prompt
checkout_rule - hidden, uses checkout_buildnumber

Example for the configuration:

checkout_buildnumber = <empty>
checkout_rule = +:tags/build-%checkout_buildnumber%

When i run the build configuration, i will be promt to enter "checkout_buildnumber". But the entered value will not be used in the checkout rule for vcs, the default value from the configuration will be used.

Example:

Root for vcs: http://vcs/

Value entered for "checkout_buildnumber": 25

Teamcity try to resolve changed from url "http://vcs/tags/build-/
I excepted that Teamcity try to resolve changed from this url "http://vcs/tags/build-25"

Am i missing something or is this not possible?