diff --git a/builder/cloudstack/config.go b/builder/cloudstack/config.go
index 5d6e9da0a..68fe778d4 100644
--- a/builder/cloudstack/config.go
+++ b/builder/cloudstack/config.go
@@ -55,9 +55,8 @@ type Config struct {
 	TemplateScalable        bool   `mapstructure:"template_scalable"`
 	TemplateTag             string `mapstructure:"template_tag"`
 
-	ctx            interpolate.Context
-	hostAddress    string // The host address used by the communicators.
-	instanceSource string // This can be either a template ID or an ISO ID.
+	ctx         interpolate.Context
+	hostAddress string // The host address used by the communicators.
 }
 
 // NewConfig parses and validates the given config.
diff --git a/builder/cloudstack/step_create_instance.go b/builder/cloudstack/step_create_instance.go
index 3b624de3c..90db2d960 100644
--- a/builder/cloudstack/step_create_instance.go
+++ b/builder/cloudstack/step_create_instance.go
@@ -30,13 +30,14 @@ func (s *stepCreateInstance) Run(state multistep.StateBag) multistep.StepAction
 	client := state.Get("client").(*cloudstack.CloudStackClient)
 	config := state.Get("config").(*Config)
 	ui := state.Get("ui").(packer.Ui)
+	source := state.Get("source").(string)
 
 	ui.Say("Creating instance...")
 
 	// Create a new parameter struct.
 	p := client.VirtualMachine.NewDeployVirtualMachineParams(
 		config.ServiceOffering,
-		config.instanceSource,
+		source,
 		config.Zone,
 	)
 
diff --git a/builder/cloudstack/step_prepare_config.go b/builder/cloudstack/step_prepare_config.go
index de397308e..8fafc809e 100644
--- a/builder/cloudstack/step_prepare_config.go
+++ b/builder/cloudstack/step_prepare_config.go
@@ -101,23 +101,25 @@ func (s *stepPrepareConfig) Run(state multistep.StateBag) multistep.StepAction {
 
 	if config.SourceISO != "" {
 		if isUUID(config.SourceISO) {
-			config.instanceSource = config.SourceISO
+			state.Put("source", config.SourceISO)
 		} else {
-			config.instanceSource, _, err = client.ISO.GetIsoID(config.SourceISO, "executable", config.Zone)
+			isoID, _, err := client.ISO.GetIsoID(config.SourceISO, "executable", config.Zone)
 			if err != nil {
 				errs = packer.MultiErrorAppend(errs, &retrieveErr{"ISO", config.SourceISO, err})
 			}
+			state.Put("source", isoID)
 		}
 	}
 
 	if config.SourceTemplate != "" {
 		if isUUID(config.SourceTemplate) {
-			config.instanceSource = config.SourceTemplate
+			state.Put("source", config.SourceTemplate)
 		} else {
-			config.instanceSource, _, err = client.Template.GetTemplateID(config.SourceTemplate, "executable", config.Zone)
+			templateID, _, err := client.Template.GetTemplateID(config.SourceTemplate, "executable", config.Zone)
 			if err != nil {
 				errs = packer.MultiErrorAppend(errs, &retrieveErr{"template", config.SourceTemplate, err})
 			}
+			state.Put("source", templateID)
 		}
 	}