change element to sibling's child node

I need to do xml to xml transform. Here is my problem. Could you please
give me the help?



Original XML file:
<?xml version="1.0" encoding="UTF-8"?>
<blueprint>
	<co>
		<co_body>
			<source_id>100</source_id>

			<CGMS_indicator>0</CGMS_indicator>
			<c_PIP_indicator>0</c_PIP_indicator>
			<c_definition>
				<service_type>100</service_type>
				<HTTP_indicator>0</HTTP_indicator>
				<number_of_streams>2</number_of_streams>
				<root_ID>100</root_ID>
				<stream_loop>
					<stream_definition>

<stream_type>2</stream_type>
						<SCID>100</SCID>

<descriptors_loop_length>compute</descriptors_loop_length>
						<descriptor_loop>

<about_descriptor>some description</about_descriptor>

<additional_descriptor>other description</additional_descriptor>
						</descriptor_loop>
					</stream_definition>
				</stream_loop>
			</c_definition>
		</co_body>
	</co>
</blueprint>




Need to do following transforms:

move CGMS_indicator and its text value under c_definition
in c_definition:
	add new element called PCR_PID_indicator, the text value equals
to the PID value of first stream in stream loop
	calculate stream number which start from root_ID and end with
root_ID+ number_of_streams, the gap is 1
	copy descriptors_loop_length and descriptor_loop from
c_definition\stream_loop\stream_definition to c_definition
in stream_loop
	rename stream_definition to stream
	recursive create stream element number_of_streams times
in each stream i:
	rename SCID to PID, the text value equals 4112+2*i
	add new element called ECM, the text value equals PID+1


the result XML file:

<?xml version="1.0" encoding="UTF-8"?>
<blueprint>
	<co>
		<co_body>
			<source_id>100</source_id>

			<c_PIP_indicator>0</c_PIP_indicator>
			<c_definition>
				<service_type>100</service_type>
				<CGMS_indicator>0</CGMS_indicator>

<PCR_PID_indicator>4112</PCR_PID_indicator>
				<HTTP_indicator>0</HTTP_indicator>
				<number_of_streams>2</number_of_streams>
				<root_ID>100</root_ID>
				<stream_loop>
					<stream>

<stream_type>2</stream_type>
						<PID>4112</PID>
						<ECM>4113</ECM>

<descriptors_loop_length>compute</descriptors_loop_length>
						<descriptor_loop>

<about_descriptor>some description</about_descriptor>

<additional_descriptor>other description</additional_descriptor>
						</descriptor_loop>
					</stream>
					<stream>

<stream_type>2</stream_type>
						<PID>4114</PID>
						<ECM>4115</ECM>

<descriptors_loop_length>compute</descriptors_loop_length>
						<descriptor_loop>

<about_descriptor>some description</about_descriptor>

<additional_descriptor>other description</additional_descriptor>
						</descriptor_loop>
					</stream>

				</stream_loop>
			</c_definition>

<descriptors_loop_length>compute</descriptors_loop_length>
			<descriptor_loop>
				<about_descriptor>some
description</about_descriptor>
				<additional_descriptor>other
description</additional_descriptor>
			</descriptor_loop>
		</co_body>
	</co>
</blueprint>




Thanks,

Jesscia