spree - Post a proudct with MWS api and Ruby on Rails -

i'm trying upload new product mws mws api , mws gem product added (like fix failed listings, because, doen't have quantity , price)

i'm trying next code:

mws = mws.connect( merchant: 'merchant', access: 'access', secret: 'secret' )

later:

product = mws::product('11333663') { upc '1234355462233' tax_code 'gen_tax_code' name 'some pduct 034' brand 'some bnd' msrp 18.9, 'usd' quantity 10 manufacturer 'some mufacturer' category :ce
details { cable_or_adapter { cable_length as_distance 5, :feet } } }

later:

submission_id = mws.feeds.products.add(product)

the product added, when excuted line:

submission_id = mws.feeds.products.update(product)

the next message displayed:

=> #<mws::apis::feeds::submissionresult:0x9d9ae78 @transaction_id="12345678", @status=#<mws::enumentry:0x9d96170 

@sym=:complete, @val="complete">, @messages_processed=0, @counts={:success=>0, :error=>1, :warning=>0}, @responses={:"0"=>#, @code=90208, @description="purge , replace not allowed feed type.">}> 2.0.0-p195 :050 > result = mws.feeds.get(submission_id.id) => #, @messages_processed=1, @counts={:success=>0, :error=>1, :warning=>0}, @responses={:"0"=>#, @code=90000, @description="http://sellercentral.amazon.com/myi/search/errorlistingssummary?batchid=7564766086">, :"1"=>#, @code=99042, @description="a value not provided \"item_type\". please provide value \"item_type\". please use product classifier or download category-specific browse tree guide seller see list of valid \"item_type\" values. information tells amazon product should classified , affects how customers can find product.", @additional_info={:sku=>"11333668"}>}>

but, when tried update inventory , price, follow error ocurred:

result = mws.feeds.get(price_submission_id.id) =>

@sym=:complete, @val="complete">, @messages_processed=0, @counts={:success=>0, :error=>1, :warning=>0}, @responses={:"0"=>#, @code=90208, @description="purge , replace not allowed feed type.">}>

what can do?

without indepth knowledge of ruby gem (and of ruby), can still point in right direction:

in mws, feeds automatically update information in amazon database. call create record identical subsequent call update it. means don't have keep track of items added amazon in past.

in terms of ruby library, should call mws.feeds.products.add(product) subsequent updates of product record , not call mws.feeds.products.update(product) @ all. latter seems create what's called purgeandreplace feeds in mws should avoid plague.

all other errors encountered seem related same root cause.