Better do merging with your windows pc in command window
e.g.:
copy /b C:\recordings\*.ts C:\recordings\mergedmovie.ts
Cutpoints will be visible though in most cases.
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For dreambox I don´t know a plugin, but you may perhaps use linux command "cat" with Telnet
cat <options> <files>
sorry - german page - wiki on CAT command:
http://wiki.ubuntuusers.de/cat.
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Better filemerging and cutting of dreambox recordings you get with Cypheros TS-Doctor (29 € after 30 days trial) - it has a filemerger inside, repairs faulty transport streams, cuts with preview, converts (mkv, mp4, AVCHD, Bluray, etc.) and lets you choose audio, subtitles, etc..
I´m satisfied in most cases.