$mail->setHeader(‚List-Unsubscribe‘, $url_k_odhlaseni) – jak na to?

Ahoj,

nejak si nevim rady s nastavenim hlavicky v mailu (List-Unsubscribe)

$mail->setHeader('List-Unsubscribe', $url_k_odhlaseni);

do mailu to takto nastavim, ale pak kdyz koukam do mailu, ktery prijde, tak tam mam:

List-Unsubscribe: =?UTF-8?B?aHR0cDovL2h1cnkucHJ5LmN6L2h1cnkvc2VxbWU=?=
	=?UTF-8?B?LmV...D1odXI=?=
	=?UTF-8?B?eWN...kY2U=?=
	=?UTF-8?B?MTk...DzOA==?=

vubec nechapu, zda je to takto v poradku, ze se to zakoduje do UTF-8

po webu to vsude popisujou, ze to musi byt:
List-Unsubscribe: <http://domain.com/member/unsubscribe/?listname=espc-tech@domain.com?id=12345N>

pouzivam NetteFramework-2.0.14-PHP5.3
diky za nejakou radu, nebo priklad jak se to spravne dela… :-)