как сделать emerge тестовой версии пакета

» eix webstorm                                                                  130 ↵
* dev-util/webstorm
     Available versions:  
     (0)    10.0.3^ms[1] ~142.4723^ms[1]
     (10)   ~10.0.4.141.1550
     Homepage:            http://www.jetbrains.com/webstorm/
     Description:         Most Intelligent WebStorm IDE for develop on js html css, 11 EAP version

» sudo emerge --autounmask-write =dev-util/webstorm-142.4723
zsh: dev-util/webstorm-142.4723 not found