[Typo3] Filling source field of a RECORDS element from a select result

[Raúl Tarrío]

Hi
I'm newbee at typo3 and I'm in troubles. I try to reference a record 
content as a search result of tt_content. Select result it's Ok, because 
in my web I have a Flexible Content in every page (CType = 
'templavoila_pi1'), but when I try to assign uid field to source field 
it doesn't work. This is my code:

10 = RECORDS
10 {
    tables = tt_content
    dontCheckPid=1
    select {
        pidInList.data = TSFE:id
        where = CType = 'templavoila_pi1'
    }
    source.field = uid
    #doesn´t work

    #source = 459
    #if I write a particular id, it works
  }

To check select result it's ok I've done it this way:

10 = CONTENT
10 {
    table = tt_content
    dontCheckPid=1
    select {
        pidInList.data = TSFE:id
        where = CType = 'templavoila_pi1'
    }
    renderObj = TEXT
    renderObj.field = uid
  }

this prints 459, the content identifier that is into one particular 
page, I mean which I want to put in source field.

¿Any idea?
Thanks,
Raúl