1and1 - SPF - DNS question

[Teebo]

I have been "battling" with my VPS/Plesk at 1and1 with hotmail for over a week now. I think the SPF was a solution, but I haven't been able to make it work.

When you sign up to a 1and1 VPS, they automatically add a 1and1 domain (lets call it 1and1domain.com). My domain is also added to the VPS (lets name it MyDomain.com... how original). So the VPS has two domains on one IP (.... XXX.XXX.XXX.XXX).

When I send email via mail() under MyDomain.com, this is what I get in the raw source:
Received: from 1and1domain.com (MyDomain.com [XXX.XXX.XXX.XXX])

The email server for the 1and1 domain is not mail.1and1domain.com, but mx01.1and1.com .

Therefore, could someone tell me if this SPF record seem ok:
v=spf1 a mx a:1and1domain.com mx:mx01.1and1.com ip4:XXX.XXX.XXX.XXX ?all

On a slightly different note... I cannot add a DNS TXT Record to the 1and1 DNS control panel! They're telling me that I need to get another nameserver to add the TXT (SPF)! If I simply point to ns.MyDomain.com and have the following in Plesk, will this be enough?

MyDomain.com. NS ns.MyDomain.com.
mail.MyDomain.com. A XXX.XXX.XXX.XXX
ns.MyDomain.com. A XXX.XXX.XXX.XXX
MyDomain.com. A XXX.XXX.XXX.XXX
webmail.MyDomain.com. A XXX.XXX.XXX.XXX
ftp.MyDomain.com. CNAME MyDomain.com.
www.MyDomain.com. CNAME MyDomain.com.
MyDomain.com. MX (10) mail.MyDomain.com.
XXX.XXX.XXX.XXX / 24 PTR MyDomain.com.
MyDomain.com. TXT v=spf1 a mx a:1and1domain.com mx:mx01.1and1.com ip4:XXX.XXX.XXX.XXX ?all

Or do I need to sign up to an external Nameserver (DNS) service?

Thanks.