Create a session variable from a response

Gatling (Open-Source)
1 

I tried to do this with EL but couldn't, so I move the code to scala but neither work.
The main idea is this one:

I get a value (142) from a response and sent it to a var called valorreq1 (OK, worked)

.check(xpath("/env:Envelope/env:Body/ns1:EResponse/Lista/Opcion/Valor", List("env" -> "http://www.w3.org/2003/05/soap-envelope", "ns1" -> "siris.autorizador.ws")).saveAs("valorreq1")))

So I need also, the length of this value into a variable called valorreq1L 

Both variables will be used in a feed in a ElBodyFile:

<Longitud>${valorreq1L}</Longitud>
<Valor>${valorreq1}</Valor>

So far so good, but:

Using this in EL:

$(fn:length(valorreq1) didn't work.

So I move the conversion to:

	.exec(
			session => session("valorreq1L", 12345)
		)
		
		but can't set this variable with the lenght of the valorreq1.
		
		
		In other works, I need something like this:
		
			.exec(
			session => session("valorreq1L", fn:length(valorreq1) )
		)






Any suggestions or idea? Thanks in advance and kind regardas



Federico