No, there is no work around to this problem, since a open part file is mandatory to use the block UI dialogs.
You could create an enhancement request at GTAC to change this behaviour.
Production: NX10.0.3, VERICUT 8.0, FBM, MRL 3.1.4 | TcUA 10.1 MP7 Patch 0 (10.1.7.0) | TcVis 10.1
Development: VB.NET, Tcl/Tk Testing: NX11.0 EAP, NX12.0 EAP
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