Help with Big string to insert in Xml Tag with PEXTCD2's xmlNode

[gio.cot]

Hi all

I would need to create an Xml file to use for consuming a Web service via LIBHTTP/http_url_post_stmf ; in this Xml, i have some tags, that can have very big strings: i.e. file?s Base64Binary content .. that can bigger than 65535 Bytes (my need is this works also in V5R4) .
For creating Xml i use xmlNode of PEXTCD2 ; example
?..
xmlNode('file'
:'xsi:type="'+ 'xsd:base64Binary' +'" '
:'ZA4aavbWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLT giPz48 ??????????.' // ß This my Big String
);
?.
How could i manage this situation ?
Any suggestion will be apreciated !!
Thanks in advance

[gio.cot]

I forgot : the value of the big string , is stored in a stream file ...
any idea ?
Thnaks in advance