Typoscript for Powermail Checkboxes

In TYPO3 I built a Powermail form for frontend editing of extended fe_users. One field holds a comma separated list of categories, and I use a Typoscript lib to fill a group of checkboxes with the entries of sys_category for this field, trying to check the ones found in fe_users field. But there is no pre-selection.

Is it the nested CONTENT? Is it the renderObj? Where is the error? Any ideas?

lib.powermail.options {
category = CONTENT
category {
    table = sys_category
    select.pidInList = 41
    renderObj = COA
    renderObj {
        10 = TEXT
        10.field = title
        20 = TEXT
        20.value = |
        30 = TEXT
        30.field = uid
        40 = TEXT
        40.value = |*
        40.if.isInList.field = uid
        40.if.value = CONTENT
        40.if.value {
            table = fe_users
            select {
                pidInList = 41
                where.dataWrap = uid = {TSFE:fe_user|user|uid}
            }
            renderObj = TEXT
            renderObj.field = category
        }
        stdWrap.wrap = |[\n]
    }
}
}