Method for establishing a bidirectional communication channel between a server (12, 131, 401) and a secure element cooperating with a telecommunication terminal in a cellular telecommunication network for exchanging data and commands, said method comprising: a- Sending through a baseband of said telecommunication terminal a first attachment request signaling message from said secure element to said server (12, 131, 401), said first attachment request signaling message comprising a MCC and a MNC of said server (12, 131, 401), and at least a part of a unique identifier of said secure element, said first attachment request signaling message having a modified field compared to a standardized attachment request message, wherein a field of said first attachment request signaling message, after the MCC and MNC, comprises the at least a part of said unique identifier and is the modified field compared to a MSIN field of said standardized attachment request message, said server (12, 131, 401) being provisioned with said unique identifier; b- Receiving the first attachment request signaling message by the server and in response thereto sending from said server (12, 131, 401) to said secure element through the baseband of said telecommunication terminal, at least a first signaling message having the length of a standardized message sent in response to said standardized attachment request message, said first signaling message having modified fields compared to the standardized message, wherein the modified fields of said first signaling message comprise: - At least a command, CMD; - A correlation identifier, Correl-ID, if further messages have to be sent from said secure element to said server (12, 131, 401), said correlation identifier being used for pairing the messages exchanged between said server (12, 131, 401) and said secure element; - A first payload comprising data; c- Executing at said secure element said command. a- Sending through a baseband of said telecommunication terminal a first attachment request signaling message from said secure element to said server (12, 131, 401), said first attachment request signaling message comprising a MCC and a MNC of said server (12, 131, 401), and at least a part of a unique identifier of said secure element, said first attachment request signaling message having a modified field compared to a standardized attachment request message, wherein a field of said first attachment request signaling message, after the MCC and MNC, comprises the at least a part of said unique identifier and is the modified field compared to a MSIN field of said standardized attachment request message, said server (12, 131, 401) being provisioned with said unique identifier; b- Receiving the first attachment request signaling message by the server and in response thereto sending from said server (12, 131, 401) to said secure element through the baseband of said telecommunication terminal, at least a first signaling message having the length of a standardized message sent in response to said standardized attachment request message, said first signaling message having modified fields compared to the standardized message, wherein the modified fields of said first signaling message comprise: - At least a command, CMD; - A correlation identifier, Correl-ID, if further messages have to be sent from said secure element to said server (12, 131, 401), said correlation identifier being used for pairing the messages exchanged between said server (12, 131, 401) and said secure element; - A first payload comprising data; - At least a command, CMD; - A correlation identifier, Correl-ID, if further messages have to be sent from said secure element to said server (12, 131, 401), said correlation identifier being used for pairing the messages exchanged between said server (12, 131, 401) and said secure element; - A first payload comprising data; c- Executing at said secure element said command.