Why UID in the accelerator config file is not used ?

Hello,
I configured the accelerator, used as console app to test, with an UID and password like that :
CONNECTION_STRING=Data Source=myMSASServer;UID=DOMAIN\myCubeUser;Password=*****;
I'm logged as DOMAIN\myPersonalUser and I launched flexmonster-proxy-ssas.exe as me with admin right.
I updated the sample client like that :
<div id="pivotContainer" style="padding-bottom: 30px;"></div>
<script type="text/javascript" src="flexmonster/flexmonster.js"></script>
<script type="text/javascript">
var pivot = new Flexmonster({
container: "pivotContainer",
toolbar: true,
report: {
dataSource: {
dataSourceType: "microsoft analysis services",
proxyUrl: "https://localhost:50005",
catalog: "Analysis Services Tutorial",
cube: "Analysis Services Tutorial",
binary: true,
},
},
licenseKey: "***"
});
</script>
When I browse the sample client page, it keeps telling me that DOMAIN\myPersonalUser does not access to the database.
That is right, but it means it does not use the user configured in the accelerator config. And I don't want to launch the accelerator executable with DOMAIN\myCubeUser as I don't want this user to have admin rights.
Can you please help showing me where I failed in the config or worstly confirm me that I have to launch accelerator executable with the same user that can access cube server ?
Thanks