Using Frames 

If the registration confirmation page (confirmPID) is designed to be displayed within frames, then add the following lines to your TS template setup:

TypoScript for frames
[globalVar = TSFE:id = {$plugin.tx_agency.confirmPID}]
config.page.frameReloadIfNotInFrameset = 1
config.linkVars >
config.linkVars =  L,agency,fD,cmd,rU,aC
config.no_cache = 1
[global]
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after setting plugin.tx_agency.confirmPID in your TS template constants.