Use ActiveSync to sync old mails

I'm trying to build a ActiveSync client application. I have a test Hotmail account, which has mails from the past 6 months, most of them unread. Hotmail uses ActiveSync v2.5. I tried the Sync command, but I'm able to get only new mails, the old (> 3 months) mails don't appear!

Am I missing something or is this how it works?

[Edit: Including the request and response Xml to make it more clearer]

Initial Request:

<?xml version="1.0" ?>
<Sync xmlns="AirSync:">
    <Collections>
        <Collection>
            <Class>Email</Class>
            <SyncKey>0</SyncKey>
            <CollectionId>00000000-0000-0000-0000-000000000001</CollectionId>
            <WindowSize>512</WindowSize>
        </Collection>
    </Collections>
</Sync>

Response:

<?xml version="1.0" encoding="UTF-8" ?>
<Sync xmlns="AirSync">
    开发者_JAVA技巧<Collections>
        <Collection>
            <Class>Email</Class>
            <SyncKey>000000000{813672f0-cc63-4308-9a33-4e8c1d0f351e}0</SyncKey>
            <CollectionId>00000000-0000-0000-0000-000000000001</CollectionId>
            <Status>1</Status>
        </Collection>
    </Collections>
</Sync>

Request:

<?xml version="1.0" ?>
<Sync xmlns="AirSync:">
    <Collections>
        <Collection>
            <Class>Email</Class>
            <SyncKey>000000000{813672f0-cc63-4308-9a33-4e8c1d0f351e}0</SyncKey>
            <CollectionId>00000000-0000-0000-0000-000000000001</CollectionId>
            <GetChanges />
            <WindowSize>512</WindowSize>
        </Collection>
    </Collections>
</Sync>

Response:

<?xml version="1.0" encoding="UTF-8" ?>
<Sync xmlns="AirSync">
    <Collections>
        <Collection>
            <Class>Email</Class>
            <SyncKey>000000000{13704907-A726-4149-8186-E3EEE98D9918}1</SyncKey>
            <CollectionId>00000000-0000-0000-0000-000000000001</CollectionId>
            <Status>1</Status>
            <Commands>
                <Add>[Contains email details]</Add>
            </Commands>
        </Collection>
    </Collections>
</Sync>

Also, the same code works great for a GMail account (which uses ActiveSync v12.0)

Apparently, the Hotmail servers respond differently to different devices. I modified the User-Agent value sent to the server to Apple-iPhone/705.18 and it started working!

Make sure you're not passing a FilterType element which would restrict the range of objects returned.

Secondly, watch for a MoreAvailable element in the Sync response which would indicate that you haven't yet received all the objects from the server.

[Edited based on comments]