getCustomVariablesValuesFromNameId with period=month

Hi there
I am trying to call the API to get custom variables for not for every day but summarized in monthes but I don’t get results.

Working:
index.php?module=API&method=CustomVariables.getCustomVariablesValuesFromNameId&idSubtable=6&idSite=23&period=day&date=2014-01-01,2014-12-31&label=xxx&format=PHP&serialize=0&prettydisplay=1&token_auth=xxx

Not Working:
index.php?module=API&method=CustomVariables.getCustomVariablesValuesFromNameId&idSubtable=6&idSite=23&period=month&date=2014-01-01,2014-12-31&label=xxx&format=PHP&serialize=0&prettydisplay=1&token_auth=xxx

Is there anything wrong in my URL?

Thanks, Andreas

To use the API: CustomVariables.getCustomVariablesValuesFromNameId

You need to specify the idSubtable. This idSubtable is different for each date / period / idSite combination. So first you must always request CustomVariables.getCustomVariables and fetch idSubtable from there, then call CustomVariables.getCustomVariablesValuesFromNameId

Hope it helps