318ci convt remote key problem

My 318ci convertible is supposed to have the soft top open by holding down the unlock key but this does not always work. I have been back and forth to the
dealer and after replacing the switches and locks etc they now say that the problem is interference from local radio waves as stated on page 30 of the handbook. I can't beleive that local radio wave interference will stop my car roof from opening using the key 9 out of 10 times when all the other functions on the key i.e. locking, unlocking, opening the boot and turning the alarm on or off still work 100%.
Has anyone else come across this problem and have any thought or info. My concern is also that if interference stops the roof from working can it make it work on its own and why cant they just change the frequency to match that of the unlocking mechanism which has never had a problem?
Thanks to all
--
M400fox

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The roof wants a continuous signal, the other functions take a pulse. If the continuous signal is being disrupted, then the roof might not open.

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