Create a record in an object from another object, also using

Guys,

Trying to run next code:

// We also create a tyrehistory record

 var v_arrh = [];

 v_arrh['name']       = v_recordId;   // the recordId of the created tyre1 will be used in the 'name' field.
 v_arrh['tyrehistoryl_firstmount']   = {!vehicletyrel_firstmount};
 v_arrh['tyrehistoryn_tyreposition']  = {!vehicletyren_tyreposition};
    v_arrh['R_tyrehistory_vehicle']   = {!R126650521.id};  // gekoppeld voertuig
    v_arrh['tyrehistorym_activity']   = '{!status#value}';  
    v_arrh['tyrehistorym_tyresize']   = '{!R_vehicletyre_tyresize#value}';
    v_arrh['tyrehistorym_supplyscope']   = '{!R_vehicletyre_supplyscope#value}';
 v_arrh['tyrehistorym_description']   = '{!R_vehicletyre_supplyscope#value}';
    v_arrh['tyrehistoryn_speedometer']  = {!R126650521.vehiclen_speedometer};
    v_arrh['tyrehistorym_tyrestatus']  = '{!R_vehicletyre_tyrestatus#value}'; // tyrestatus
    v_arrh['tyrehistorym_serialnumber']  = '{!R262070.tyre1m_serialnumber}'; 
    v_arrh['tyrehistorya_tread']   = {!vehicletyrea_tread};
    //v_arrh['tyrehistoryd_date']    = {!createdAt};  //deze geven problemen indien 'ingesterd' bij createRecord 'v_arrh' waarde
 //v_arrh['tyrehistoryd_date']    = '{!createdAt#iso}'.substring(0,10);
    //v_arrh['tyrehistoryd_speedometerdate']  = '{!R126650521.vehicled_speedometerdate#iso}'; 
    // test jorrit hieronder
    //v_arrh['tyrehistoryd_date']    = {!createdAt};  //deze geven problemen indien 'ingesterd' bij createRecord 'v_arrh' waarde
 
    
    rbv_api.printArr(v_arrh);      

    //var v_recordIdh =
    rbv_api.createRecord("tyrehistory", v_arrh);

The creation of the record works only if we leave out the 'tyrehistoryd_date' and 'tyrehistoryd_speedometerdate'

However this is required for correct operations in the application as you can imaging.

Now it must be something like a format in with we have to assign to the values,

Question: wat should we use as format; as you see we use: '{!createdAt#iso}'; but that does not work.

Please help

Thanks in advance,

BTW, IramK if you also follow this post, i admire your sharp questions, looks you'r doing a creat job improving the Rollbase product!