Unable to pass secure values between linked ARM templates

I am trying to output a secret created in one linked template and reference this as a parameter in another. Test scenario:

{ "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#", "contentVersion": "1.0.0.0", "parameters": { "templateBaseUrl": { "type": "string" } }, "variables": { "deployment1url": "[concat(parameters('templateBaseUrl'), '/deployment1.json')]", "deployment2url": "[concat(parameters('templateBaseUrl'), '/deployment2.json')]" }, "resources": [ { "apiVersion": "2017-08-01", "name": "deployment1", "dependsOn": [], "type": "Microsoft.Resources/deployments", "properties": { "mode": "Incremental", "templateLink": { "uri": "[variables('deployment1url')]", "contentVersion": "1.0.0.0" }, "parameters": {} } }, { "apiVersion": "2017-08-01", "name": "deployment2", "dependsOn": [], "type": "Microsoft.Resources/deployments", "properties": { "mode": "Incremental", "templateLink": { "uri": "[variables('deployment2url')]", "contentVersion": "1.0.0.0" }, "parameters": { "testInput2": { "value": "[reference('deployment1').outputs.testOutput1.value]" } } } } ], "outputs": {} } 

Deployment1:

{ "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#", "contentVersion": "1.0.0.0", "parameters": { }, "resources": [], "outputs": { "testOutput1": { "type": "securestring", "value": "thisisapassword" } } } 

Deployment2:

{ "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#", "contentVersion": "1.0.0.0", "parameters": { "testInput2": { "type": "securestring" } }, "resources": [], "outputs": {} } 

Running this scenario throws the error "Unable to process template language expressions for resource '/subscriptions//resourceGroups/testrg1/providers/Microsoft.Resources/deployments/deployment2' at line '34' and column '9'. 'The language expression property 'value' doesn't exist, available properties are 'type'.'"

So '.value' on the securestring output doesn't work, if I change the reference parameter to

"testInput2": { "value": "[reference('deployment1').outputs.testOutput1]" } 

the errors changes to 'Deployment template validation failed: 'The provided value for the template parameter 'testInput2' at line '5' and column '23' is not valid.'.'

Is it possible to achieve what I am doing?

Thanks in advance