Trying to get Powershell to work with an API - powershell

Question

I am trying to write a Powershell script to work with a Microsoft API, and being new to this, I have come across an error that I cannot seem to get past.
Error:
Cannot find an overload for "UpdateDeviceValues" and the argument count: "3".
At C:\PowerShellScripts\API-UpdateDeviceValues-ICC.ps1:13 char:37
+ $accounts = $pmws.UpdateDeviceValues <<<< ('18B81F1FD790','DisableICC','True');
+ CategoryInfo : NotSpecified: (:) [], MethodException
+ FullyQualifiedErrorId : MethodCountCouldNotFindBest
From my searches, it seems that the API is requiring three values to be sent to it, but that is what I am sending.
My code:
$pmws = New-Object PrincipalManagement;
$pmws.Credentials = $cred;
$pmws.url = "http://172.31.9.2/bss/PrincipalManagement.asmx";
$accounts = $pmws.UpdateDeviceValues('18B81F1FD790','DisableICC','True');
$accounts
Any help with this error would be much appreciated. I am rather new to this, getting Powershell to work with APIs.
This is the SOAP 1.1 example for the API.
POST /bss/PrincipalManagement.asmx HTTP/1.1
Host: 172.31.9.2
Content-Type: text/xml; charset=utf-8
Content-Length: length
SOAPAction: "http://www.microsoft.com/iptv/bss/UpdateDeviceValues"
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope">
<soap:Body>
<UpdateDeviceValues xmlns="http://www.microsoft.com/iptv/bss">
<deviceExternalID>string</deviceExternalID>
<deviceValues>
<DeviceValue Key="string" Value="string" />
<DeviceValue Key="string" Value="string" />
</deviceValues>
</UpdateDeviceValues>
</soap:Body>
</soap:Envelope>
I can run this in PowerShell:
> $pmws | Get-Member
I get a long list of the APIs, and in that list is the one I am trying to use...
TypeName: PrincipalManagement
Name - MemberType - Definition
UpdateDeviceValues - Method - System.Void UpdateDeviceValues(string deviceExternalID, DeviceValue[] deviceValues)
Much thanks to Chamele0n! Answer found!
I was missing how to properly format the parameters when calling the method.
This works!
$Account = "18B81F1FD790"
$deviceValue = New-Object ($ns + ".DeviceValue")
$deviceValue.Key = "DisableICC"
$deviceValue.Value = "True"
$accounts = $pmws.UpdateDeviceValues($Account, $deviceValue)
Thanks,
Jason...