Complex XML structure to FlatFile

Dear Expertise,

I have a scenario, where I need to convert complex XML structure to Flat File with Fixed length. In my case XML is IDOC XML. But for understanding purpose I am giving the following structrue.

Suppose I have XML structure as follows

*****************************************************************************************

<sub>

<name>test</name>

<empno>1212</empno>

<sub1>

<lastname>lastname</lastname>

<middlename>middelname</middelname>

<sub2>

<city>city</city>

<country>country</country>

</sub2>

</sub1>

<sub>

***************************************************************************************

How to configure the receiver adapter for fixed field lengths in this case. I need configuration parameters for this requirement.

Advanced Thanks,

Gujjeti